Installing the supply of CO2 carbon dioxide to the aquarium with your own hands. The simplest system for supplying CO2 to an aquarium How to replace CO2 in an aquarium

Many novice aquarium owners wonder why carbon dioxide is needed. It turns out to be necessary for fish, since otherwise they will not be able to actively develop.

CO2 - what is it?

Sooner or later, every serious aquarist is faced with the question of supplying the aquarium with CO2. And for good reason. Why do aquarium plants need it? So, CO2 - what is it?

We all know that aquatic plants feed primarily on carbon dioxide dissolved in water. This is CO2. In nature, plants obtain it from the body of water in which they grow. Since the volume of water in natural reservoirs is very large, its concentration in them is usually constant. But the same cannot be said about aquariums.

Plants quickly use all the CO2 gas from the aquarium water, and its concentration will not be restored by itself, because the aquarium is a closed system. Even the fish contained in it will not be able to compensate for the lack of CO2, since they exhale such a tiny share of it that it will never be enough for plants. As a result, aquarium plants stop growing.

In addition to the fact that plants stop growing due to a lack of CO2, water in which its content is low has increased hardness (pH), which is detrimental to them. Even inexperienced aquarists have probably noticed that after adding plants, tap water becomes harder than it was in an empty aquarium. This is explained by the fact that carbon dioxide promotes the appearance of carbonic acid in water, which reduces hardness. That is, it is important to understand: the less CO2 in the water, the higher its pH.

Soda as a source of CO2 for an aquarium

For nanoaquariums up to 20 liters, not everyone wants to deal with a CO2 cylinder unit. You can make a CO2 generator using mash or soda. But you can do it easier. There is an ancient and undeservedly forgotten method of supplying CO2 - using carbonated water. Carbonated water is a kind of concentrate of carbon dioxide already dissolved in water.

The CO2 content in soda is usually about 5000-10000 mg/l, and after opening the bottle it tends to 1450 mg/l. If you calculate how much carbonated water is needed to bring the CO2 concentration in the aquarium to 10 mg/l, it turns out to be quite economical. Fresh soda only needs 20 ml per 10 liters of aquarium water, which will give 10 mg/l CO2 in the aquarium. It is enough to simply add soda along with fertilizers in the morning. After standing, you can add soda in large quantities, as carbon dioxide disappears.

Approximately, 1 liter of soda is enough for a 10-20 liter aquarium for a month. Any sparkling water will do, except salt water, of course. It's better to use the cheapest ones. They are usually made from tap water :). It is better not to increase the CO2 concentration to more than 10 mg/l using this method.

Firstly, it is not known how much carbon dioxide your soda contains (5000 mg/l or 10000 mg/l). Secondly, large fluctuations in CO2 concentration in the aquarium are not desirable. After adding soda, the concentration will gradually decrease due to consumption by aquarium plants. Constant fluctuations in CO2 from 10 mg/l to zero and back are not scary. But fluctuations from 20-30 mg/l to zero are much worse for the balance in the aquarium.

Advantages of the method:

no reactor for dissolving CO2 and a bubble counter are needed, since CO2 is already dissolved in carbonated water;
ease of use;
economical in the short term;
Suitable for nano aquariums.

Disadvantages of the method:

unstable CO2 concentration in the aquarium;
the price of 1 gram of CO2 is the highest of the listed methods, that is, uneconomical in the long term and for large-volume aquariums;
weak CO2 supply compared to other methods.
For most plants, incl. rare and difficult, just a small addition of CO2 is enough, i.e. It is better to underfeed than to overfeed. Try to keep the indicator in the green zone.

However, if you suddenly find that the indicator has turned yellow or completely discolored, there is no reason to panic.

If everything is fine with the fish, there is no need to change the water, you can remove the bottle and put it in the refrigerator for a while, the plants will gradually absorb the excess carbon dioxide, watch the fish, in my aquariums the indicators often went off scale, especially at first, but not a single case of fish death from -there was no CO2 poisoning.

When optimal saturation conditions are found, there is no point in shutting off the supply of carbon dioxide at night; a small morning excess of CO2 will be taken up by the plants in the evening; this regime repeats the daily fluctuations in gas composition and pH in natural reservoirs and has a beneficial effect on the growth of all plants.

IMPORTANT: when using external filters or filters of other models as a reactor, under no circumstances supply CO2 BEFORE the filter elements. CO2 should be supplied only AFTER all fillers, otherwise the microflora inhabiting the filter materials may die.

When recharging the bottle, do not hang the free end of the tube over the edge of the aquarium - the pressure of the filter can push the water over the edge and it will flow onto the floor.

If you are forgetful, I do not recommend using the clamp wheel on the IV tube. If you close it for a long time during fermentation, the increased pressure inside can rupture the bottle.
There is no need to place the bottle on the warm lamps of the aquarium - the fermentation will be too intense and will end in a short time.

If you have several aquariums on your farm, I advise you to provide each of them with its own personal bottle. On my farm there are different aquariums with a capacity of 150 to 400 liters, I recharge all the bottles at once, about once every 10-15 days.

Braga

Braga is the basis of CO2 for an aquarium, which consists of yeast, water and sugar. There are bread, dry and brewer's yeast, but dry and brewer's yeast are more suitable for mash. All ingredients are mixed and sealed in a vacuum container. The process of yeast fermentation is completely different from the process of photosynthesis, whereby the necessary gas is released for the reservoir by the use of sugar by the yeast.

To make a mash plant you will need 2 transparent plastic bottles with a volume of 1.5–2 liters. Raw materials of water, yeast and sugar are poured into the bottle and closed. The CO2 generator is connected to the gas separator via a tube or hose (a regular dropper is suitable for the tube). To dissolve the gas in the aquarium, you need to attach a filter with a tube and a special pump for spraying. The pressure can rupture the bottle, so a valve inserted into the medical syringe is used to prevent this problem. It is installed on the lid of the main vessel and serves as a gas bubble counter. It is most convenient to make a CO2 system with two generators.

Balloon installation

CO2 is supplied to some large aquariums through a system consisting of a main cylinder and a reducer, which prevents the gas pressure from rising. Solenoid and check valves designed to control gas and prevent the release of water into the reducer. The system also includes a tube through which gas enters the aquarium and a special fast carbon dioxide sprayer - a diffuser. Such a system is called a balloon installation; it is easy to use and looks aesthetically pleasing (does not spoil the appearance of the aquarium).

Means of controlling the carbon dioxide content in the aquarium.

To control the intake of CO2 in an aquarium, there is, in fact, one way - measuring acidity (PH) and carbonate hardness (KH), followed by determining the concentration of CO2 in the water using the table Table of carbon dioxide content in the aquarium (CO2, CO2). It is somewhat more convenient to do this procedure using the calculator.php#j One feature is that in our calculator, when entering the pH value, you need to use a dot rather than a comma as a decimal sign.

The use of drop checker(DC). The PM is a container, one part of which is filled with a standard indicator solution - water with KH 4, into which an indicator analogue of the pH test is added. The second part of the container is open and aquarium water flows into it. Both parts of the container are designed in such a way that there is always an air cushion between the indicator solution and the aquarium water. A kind of “siphon in reverse.”

When the concentration of CO2 in aquarium water increases, part of it leaves it into the air cushion, equalizing the partial pressure of CO2 in the water and the air above it. At the same time, CO2 dissolves in the indicator solution, also equalizing the partial pressure. As a result, the concentration of CO2 in the aquarium water and in the indicator solution becomes the same.

As the concentration of CO2 in the indicator solution changes, its pH also changes, to which the indicator reacts by changing color. By its color you can judge the concentration of CO2. When the concentration of CO2 in water decreases, everything happens in the reverse order. This is a permanent do-it-yourself pH test for Drop Checker (DIY CO2 Drop Checker).

A very convenient device with one significant drawback - until all the above-described processes take place, 2-3 hours pass - the delay time of the frequency response. During this time you can add all the fish. Therefore, at the stage of testing the gas supply, I would recommend using tests and a calculator in order to have “instantaneous” values, and using DC for general control in an already established mode.
Bubble counter.
To track the amount of CO2 entering the aquarium, a bubble counter is used - a small transparent container filled with water and embedded in the gas supply line. CO2 passing through it is visually observed in the form of bubbles passing through the water at equal intervals from one another. I will sell CO2 balloon equipment, diffusers (St. Petersburg) (fifth photo on the left, seventh photo on the right). Again, I don’t understand why pay when you can just as easily take a filter from a drip for this purpose))).

It is advisable to install a check valve under the bubble counter so that if the gas pressure drops, water does not flow down into the tube. The check valve should also be placed in front of the rowan branch or diffuser in the aquarium. Check valve in a carbon dioxide supply system for an aquarium
-Pearling - bubbling of plants. A somewhat subjective method of monitoring the CO2 content in an aquarium.

However, the fact remains that an experienced aquarist, knowing the chemical composition of the water in his aquarium and his lighting, can quite accurately draw a fairly accurate conclusion about the concentration of CO2 in the water based on the bubbling of plants. Moreover, different plants react to this differently.

The simplest way to supply carbon dioxide

The main element is a vessel (a two-liter plastic bottle, for example) with ordinary mash. Raw materials for fermentation are poured into the bottle:

sugar - 300 g;
yeast - 0.3 g.

The raw materials are poured with 1 liter of water, the sugar is not stirred. A tube (hose) is hermetically inserted into the bottle cap at one end, and the other end of the tube is lowered into the water of the aquarium. When the fermentation process begins, the carbon dioxide released is released into the water.

To prevent clots of the mash mixture from entering the aquarium, you can tie a small plastic bottle to the main container and attach 2 more tubes so that the gas and fermentation products first enter the small container, and only then into the aquarium.

This method has significant disadvantages:

the impossibility of adjusting the amount of carbon dioxide supplied to the aquarium water and the instability of its supply;
The short duration of operation of such a system is up to 2 weeks.

DIY CO2 generator

To make a working gas generator with adjustable supply, a little more materials and labor will be required.

The principle of operation of the installation is to gradually supply citric acid from one vessel to another, where baking soda is located. The acid is mixed with soda, and the CO2 released as a result of the chemical reaction enters the aquarium tank. Let's look at the manufacturing process step by step.

Creation of the device

Take two identical liter plastic bottles. In the lids, you must carefully drill 2 holes with a wood drill for the subsequent installation of tubes (hoses). One tube with a check valve connects container No. 1 to container No. 2.

A tee tube is inserted into the second holes of the caps, one branch of which also has a check valve. Hoses with check valves should be inserted into container No. 2, and a small tap should be installed on the central branch of the tee to regulate the flow.

Necessary reagents

Bottle No. 1 is filled with an aqueous solution of soda (60 g of soda per 100 g of water), and bottle No. 2 is filled with a solution of citric acid (50 g of acid per 100 g of water). Caps with tubes must be screwed tightly onto the bottles.

All joints and openings must be securely sealed with resin or silicone to prevent gas leakage. The ends of the first hose must be lowered into the solutions, and the left and right tubes of the tee must be installed above the level of the solutions - CO2 will pass through them.

Beginning of work

To start the gas generation process, you need to press on bottle No. 2 (with citric acid). The acid enters the soda solution through the first hose, and a reaction occurs, releasing carbon dioxide. The non-return valve of the pipe does not allow the soda solution under pressure to enter container No. 2.

The released gas passes in two directions:

into a bottle with citric acid, creating pressure for continuous generation,
into the central pipe of the tee, through which CO2 enters the aquarium.

Using the tap you can regulate the gas flow. If instead of a homemade tee you use hoses from a medical dropper, then an additional gas bubble counter will appear, which is very convenient for creating an accurate concentration of CO2 in aquarium water.

Some owners of ornamental fish use an adapter to connect the outlet hose to the outlet of the internal filter. In this case, carbon dioxide diffuses, and it is better absorbed by plants.

In this article we will look at all issues related to co2 in an aquarium.

Let's look at it: what is CO2 for an aquarium, how to make CO2 for an aquarium with your own hands, a CO2 generator for an aquarium with your own hands and all related questions.

General information

All tissues of any living organism consist of water and organic compounds. The basis of such compounds is carbon. Carbon is the building material from which the biological mass of living organisms is “built.” Animals can take it from organic compounds, but plants can “extract” it from inorganic matter. The most favorable in this regard for aquarium plants will be CO3 carbonates and CO2 carbon dioxide dissolved in water. CO3 enters the aquarium either during water changes (temporary hardness KH) or when dissolving calcareous shells or decorations directly in the aquarium itself. Carbon dioxide CO2 enters the aquarium in two ways: from the respiration of living organisms (fish, invertebrates) or from the outside. By “from the outside” we mean forced saturation of CO2. Both mechanisms for producing carbon complement each other, but do not replace each other.

During photosynthesis, plants consume carbon in the light. The more light, the more carbon plants can consume, which directly affects their growth. But besides carbon, plants also need other elements: iron, nitrogen, phosphorus and others. They come in the form of fertilizers. Therefore, the supply of carbon and fertilizers must be balanced. If there is an excess of one element and not enough of another, an imbalance will arise. Which can be “taken advantage of” by unwanted “guests” - algae.

CO2 needs to be supplied only during daylight hours while plants are photosynthesizing. In the dark, the supply of carbon dioxide is undesirable, since it is not only useless, but can cause poisoning in aquarium fish. Aeration must be turned off during the day, as air bubbles create fluctuations in the water column, and this pushes out CO2. And on top of that, plants release oxygen during photosynthesis. And in the dark, after turning off CO2, you need to turn on aeration.

Biological method of producing CO2 using the “mash” type

Supplying CO2 to the aquarium

There are several ways to supply co2 to an aquarium:

Biological. Production of carbon dioxide CO2 as a result of alcoholic fermentation (“mash”, “mash”)
Chemical. Production of CO2 by chemical means, usually in devices operating on the principle of the Kipp apparatus (“Kipp apparatus”, “geyser”)
Electrochemical. CO2 formation during electrolysis. It is quite complicated and the type of use of hydrogen is somewhat dangerous. Therefore, we will not consider it in detail in this article.
Mechanical. CO2 supply from cylinders filled with carbon dioxide in advance (“balloon system”, “CO2 cylinder”)

Let’s look at all of the above methods in more detail, through the prism of “do-it-yourself co2 into an aquarium.” Since there are also branded devices, but why spend money if you can do it all yourself.

Biological method for producing carbon dioxide

The easiest way to get carbon dioxide for an aquarium is to prepare ordinary mash.

To make it we will need: a plastic bottle, 1 liter of water, 300 g of sugar, 0.3 g of yeast. Everything is poured into a bottle, filled with water, but the sugar is not stirred. A tube is hermetically inserted into the cork of the bottle, the hose of the second end of which is lowered into the aquarium. But in order to prevent the mash mixture from getting into the aquarium, the end of the tube from the main bottle is inserted into the stopper of a smaller plastic bottle, and the other piece of the tube from the same, small bottle is diverted into the water, and that’s it, carbon dioxide in the aquarium!

Such a do-it-yourself co2 system for an aquarium is not complicated, but it has its drawbacks:

short duration of work – up to 2 weeks
instability of CO2 supply to the aquarium
it is impossible to regulate the amount of gas supplied to the water

Chemical method

Let's look at how to make a co2 generator for an aquarium with your own hands. This option will require a little more time and materials than the previous method.

A carbon dioxide generator for an aquarium is not complicated. The principle of its operation is to supply citric acid from one vessel, where it is located, to another, where baking soda is located. As a result of the chemical interaction of the two components, CO2 is released, which is discharged into the aquarium.

Manufacturing and launch process

In order to make such a co2 generator for an aquarium, you will need two plastic liter bottles. Two holes are made in the lids for installing tubes in them. One tube, with a check valve, connects bottles No. 1 and No. 2 to each other.

In the second holes that we made in each of the covers, we insert a tee tube, one of the holes of which also has a check valve. All tubes with check valves must be inserted into bottle No. 2, and we install a faucet on the central branch of the tee, which will be used to regulate the flow.

For our aquarium co2 system to work, we need to fill the bottles with reagents. In container No. 1 we place an aqueous solution of soda (per 100 g of water - 60 g of soda). And in container No. 2 an aqueous solution of citric acid (per 100 g of water - 50 g of citric acid).

All joints must be reliably sealed. The ends of the first tube must be in the solution for circulation between the bottles. But the left and right tubes of the tee need to be installed above the solution level for the passage of carbon dioxide.

To start the system, you need to press on bottle No. 2 with a solution of citric acid. The acid solution flows through the first hose (the check valve prevents the reagent from flowing back) into bottle No. 1 with the soda solution. As a result of the chemical reaction, carbon dioxide is released. The released CO2 comes out in two directions: into the central pipe of the tee, through which it enters the aquarium; and into bottle No. 2 with citric acid to create pressure that will ensure continuous generation.

Chemical method for producing CO2 using the method we described

Mechanical method of producing CO2

CO2 cylinder for aquarium - This is the most advanced and efficient carbon dioxide supply system, but quite expensive. They consist of a cylinder filled with liquefied CO2 (at a pressure of about 50 atm), a reducer that reduces the gas pressure to the required parameters (1.5-2 atm), a control valve and an electronic valve that allows you to automate the supply of gas to your aquarium.

In the factory version there are cylinders from 50 ml and more. A do-it-yourself CO2 cylinder system for an aquarium is usually made from a carbon dioxide fire extinguisher cylinder. But you can use other options that you find. The cylinder is filled with gas, and the components listed above are connected.

There are two disadvantages of such a system: the high cost of components, and the danger from having a cylinder with high gas pressure in the house.

There are still more advantages of CO2 cylinders for an aquarium: high stability of CO2 supply, large gas supply, full automation of supply, fine adjustment of supply.

Another mechanical method is regular carbonated water. Primitive and simplest method. Used in small aquariums, on a temporary basis, when nothing else is available.

Used in several ways. A needle with a tube is stuck in, the other end of which is placed in the aquarium. Or, tritely, a glass of such water is added to the aquarium every day.

Gas equipment for producing carbon dioxide for an aquarium

Methods for dissolving CO2 in water

Let's also consider ways to dissolve carbon dioxide in water. Such devices are called reactors. There are passive type reactors (gas dissolves upon contact with water, or when bubbles rise to the surface) and active type (gas is forced to dissolve in a water flow organized for this purpose).

Passive type reactors:

"bell" reactor. It is a cap placed bottom up. A hole is made in the bottom into which gas is supplied through a tube. Dissolution occurs at the interface between gas and water. The larger the cap area, the better.
"Linden branch" reactor. A rowan or linden branch, without bark, is placed in a gas supply tube, and through the end cut of the branch, CO2 bubbles enter the water.
"diffuser" reactor. The container, a diffuser, is placed in the aquarium. The upper part is a membrane through which gas enters the water.

Active type reactors:

interior. The bell is installed inside with the bottom down, at the filter outlet. Gas is supplied to its lower part, and the gas rushes to the bottom with a stream of water and dissolves well in water.
external. It is implemented according to the internal principle, the difference is that the container into which the gas is supplied is embedded in the outlet hose of the external filter.

How to determine the required amount of carbon dioxide in an aquarium can be found in our calculator article (table).

By feeding the aquarium flora with carbon dioxide, you provide conditions for their normal life and growth. Anyone can carry out this process, and everyone can organize and make co2 for an aquarium with their own hands!

Video of making a gas cylinder system with your own hands:

If you ask almost any person what green plants eat, you will usually hear about fertilizers - nitrogen, phosphorus and potassium. For some reason, the school curriculum has firmly drilled this knowledge into our heads. The answer is somewhat less common: “Sunlight and water.” But when asked what plants breathe, the majority answers: “Carbon dioxide. And they exhale useful oxygen.” Of course, all of these answers are wrong. In reality, everything is completely different...

Like almost all living things on planet Earth (with the exception of anaerobic bacteria and the inhabitants of deep-sea sulfur volcanoes - “black smokers”), green plants breathe oxygen. But they don’t inhale carbon dioxide at all, but... eat it! It is from the carbon that is included in its composition that plants build all their organs and tissues; it serves as both fuel and building material for them. Therefore, one of the most important factors in the growth of green plants is the content of carbon dioxide, CO 2 , in the environment (in the air for land plants and in water for aquatic plants). We'll talk about it today...

A little educational program. About photosynthesis.

As you know, almost all substances that make up any living organism (proteins, fats, carbohydrates, nucleic acids, etc.) consist of 99% of only three chemical elements: carbon, oxygen and hydrogen. The remaining 1% consists of macroelements: nitrogen, phosphorus and potassium, as well as the so-called “microelements” (primarily iron, calcium, magnesium, zinc, and others in smaller quantities - almost half of the periodic table). Green plants have an amazing mechanism that allows them to independently synthesize organic substances from carbon dioxide and water. Under the influence of sunlight, a special substance contained in their cells - the green pigment chlorophyll - produces simple sugar - glucose - from CO 2 and H 2 O, and from it, with the help of macro- and microelements, enzymes can make proteins, fiber, starch and everything the rest that is needed for the construction of a plant organism. During this reaction, oxygen is released into the environment. Plants use a small part of this oxygen for respiration, and the rest is released into the air or water.

So, for normal growth and development of higher green plants, a sufficient amount is necessary:

carbon dioxide;
water;
sunlight;
macroelements (nitrogen, phosphorus, potassium);
microelements (iron, calcium, magnesium, zinc, etc.)

In chemistry and biochemistry there is such a concept - “reaction limiting factor”. What this is is well understood by those who often go hiking: the speed of the group is always equal to the speed of the slowest of its members, who is the “limiting factor.” The same applies to the growth of aquarium plants. They have enough water in abundance (they live in it!), macro- and microelements come from the soil, from water and with the application of fertilizers, making good bright lighting is also not a problem, but difficulties arise from time to time with CO 2. This is what becomes the “limiting factor” in the aquarium. Why? Why do carbon dioxide problems occur in an aquarium but not in nature? Let's figure it out...

Why is there a deficiency of CO 2 in an aquarium?

Look at the biotope of any natural fresh water body. There are usually few aquatic plants there, and they sit sparsely, and the bottom is covered with organic sediments, in which a variety of micro- and macroorganisms, mainly invertebrates, live in abundance. And there are plenty of fish and tadpoles... And all of them - from microorganisms that process bottom sediments to fish and frogs - release significant amounts of CO 2 into the water. A different matter is a typical planted aquarium, which, as a rule, is densely planted with plants, and there are few fish in it, and they are small (because most large fish spoil the plants). The usual population of our aquariums is small schooling characinka and guppies with platies, which, due to their small size and slow metabolism of carbon dioxide, emit very little carbon dioxide.

But in our ordinary aquariums there is plenty of light, and usually there is also enough nitrogen and phosphorus. So it turns out that CO 2 becomes the “limiting factor”. Some plants, when deficient, are simply inhibited in growth and eventually die, while others have adapted to extract CO2 from minerals themselves, decomposing bicarbonates dissolved in any water. In this case, insoluble calcium salts are formed as a “by-product”, which fall out on the leaves of such plants in the form of a rough, unsightly crust (on which unicellular diatoms quickly settle). This trick can be performed by elodeas, anubias, hornworts and some other species that live in nature in stagnant bodies of water and are faced with periodic carbon dioxide deficiency there. So if we want the plants to look like they do in the pictures on the Internet, and not to be skinny, sad and drooping tails covered with limescale and algal growth, then willy-nilly we will have to think about adding carbon dioxide to the aquarium.

If you are accustomed to approaching such problems more meticulously, and my brief explanations do not convince you, I advise you to refer to the scientific article at this link, in which all this is explained in detail from the point of view of chemistry and biochemistry:

Let's move on to practice. But first, a little warning:

Don't overdo it!

Of course, CO2 supplied to a planted aquarium in reasonable quantities stimulates the growth and development of plants. But the key word here is “reasonable”! Before moving on to the description of carbon dioxide supply systems, I would like to remind you that, as you know, through negligence you can break parts of the body that are not too prone to fractures ;-) . And if excessive aeration, for example, is difficult to harm the aquarium, then excess CO 2 can easily poison your fish and shrimp, so control over its concentration is necessary. And the first thing you need to purchase before you start feeding your plants with carbon dioxide is an indicator of its content. The optimal concentration of CO 2 in an aquarium is 5-20 mg/l. A carbon dioxide content of less than 3 mg/l threatens plants with starvation, and 30 mg/l is a concentration dangerous for fish and invertebrates.

Carbonate hardness, water acidity and CO 2 concentration are interdependent parameters, so knowing two of them you can determine the third. Indicators of carbonate hardness (kH) and acidity (pH) of water, as well as this table will help you more accurately understand what the concentration of CO 2 is in your aquarium:

Using a bubble counter, you need to adjust the flow of carbon dioxide from your system into the aquarium so that its content is in the “green” region. If your aquarium is stable, then it is usually enough to adjust the indicator once every month or two, remember the gas supply rate in bubbles per minute, and then simply maintain the supply at this constant rate. At night, the CO 2 supply must be turned off (manually or with an automatic valve), otherwise the pH of the water will drop significantly at night.

You can simplify the procedure by purchasing a glass indicator of the CO 2 content in water, the so-called “drop checker”. The color of the liquid in it changes depending on the concentration of carbon dioxide, and means the same as the colors in the plate in the figure: yellow - a lot of CO 2, blue - little, and green - just right. It is better to never let it turn yellow: usually the liquid in a drop checker turns yellow when the concentration has exceeded a level dangerous for fish. Please also note that the “drop checker” is a rather “braking” device and does not respond to changes immediately, so after changing the gas flow rate you must wait half an hour before its readings begin to correspond to reality. The indicator liquid in drop checkers lasts up to three months, then it turns pale, cloudy, and requires replacement. By the way, liquids for drop checkers of different brands sold in pet stores are completely interchangeable (their composition is exactly the same).

Many literary sources advise, given the usual carbonate hardness in our aquariums of about kH = 4, to set the carbon dioxide supply rate to about 5 bubbles per minute for every 50 liters of aquarium volume. It is clear that this figure is approximate, but it is better to regulate the flow using indicators by starting with it. otherwise, again, there is a risk of “overdoing it”.

Where to get CO 2 from?

So, from all of the above, we understood that since CO 2 is so necessary in the aquarium, and the fish do not excrete it enough, then it should be supplied forcibly. But where to get it from? There are many options. If you have a small aquarium of 10-30 liters, and you are near it most of the day, then you do not need any CO 2 generator at all: in such a jar it is enough to carefully pour a 20 ml glass of the most ordinary glass into the aquarium 2-3 times a day drinking carbonated water from a bottle (of course not sweet, not salty or mineral). It’s better to take the cheapest one, which is made from tap water - it’s guaranteed to have no harmful additives. If you have a larger aquarium, you will need a carbon dioxide generator, fittings for supplying it, a bubble counter and a reactor that ensures its dissolution in water at the required concentration. Let's start with generators.

Fermentation generator

Drexel bottle

The oldest method of producing carbon dioxide in the aquarium hobby is the fermentation method, based on the reaction of sugar and yeast. The principle is known and understood by everyone: yeast in an aqueous solution eats sugar, turning it into alcohol and carbon dioxide. If the process is carried out in a sealed container, then the resulting CO 2 can be fed into the aquarium through a tube. The advantages of the yeast method are clear - “cheap and cheerful”: sugar and yeast cost pennies, everyone can knead the brew, and, it would seem, there are no costs. But it's not that simple!

Firstly, yeast eats sugar quite quickly, and CO 2 is released normally only in the first couple of days. Then the solution runs out of sugar, and the yeast itself is poisoned by the resulting alcohol and dies. In order to slow down the process, aquarists have come up with many different tricks: from the banal “mix, but do not stir” (so that the sugar dissolves gradually) to the addition of soda and various thickeners (gelatin, agar, starch), which make it difficult for yeast cells to get to the coveted sugar . But even the most advanced fermentation device “bubbles” CO 2 for no more than two or three weeks, after which it still needs to be disassembled, the foul-smelling contents drained and refilled.

Secondly, during the period of intense fermentation, organic foam forms in the reactor, which can, once it gets into the aquarium, cause a “biochemical catastrophe” in it, so carbon dioxide from such an apparatus must be passed through “ Drexel bottle"so that foam, drops, etc. remain in it and do not reach the aquarium. It is best to pour a little baking soda solution into the bottom of such a bottle so that CO 2 gurgles through it, clearing not only foam, but also alcohol vapor, acetic and other acids formed during fermentation.

Thirdly, if you skip the end of fermentation, the excess gas pressure in the reactor may be replaced by insufficient pressure, and instead of supplying gas to the aquarium, water from the aquarium may begin to flow into the reactor. This means that a check valve is needed to shut off the tube in such a situation.

Finally, fourthly, the rate of gas release during fermentation is very unstable, depending on the ambient temperature, the type and quality of yeast and many other factors, and it will have to be constantly monitored using a bubble counter, at the beginning of the process limiting the flow of gas into the aquarium, and at the end - opening to the fullest.

To be fair, it should be said that since there are quite a few fans of the “fermentation” method among aquarists, which is considered environmentally friendly and natural, some well-known manufacturers of aquarium equipment, following their beliefs, produce industrial kits for producing CO 2 by fermentation. As a rule, these kits include a replaceable bottle with “biogel” (a solution of sugar and a special thickener) and special “slow” yeast, as well as all the necessary accessories. The contents of the bottle usually work for about a month, after which you will have to buy a new bottle.

An example of such a set:

CO2 system JBL ProFlora bio80 eco 2 with refillable cylinder for aquariums from 12 to 80 l
CO2 system JBL ProFlora bio80 eco 2 with refillable cylinder and mini CO2 reactor for aquariums from 12 to 80 l

Replacement bottle:

In general, the simplicity and cheapness of the “mash” turns out to be apparent, but it requires constant care. What other options are there?

Chemical method

Kipp apparatus

The second method of obtaining CO 2 is much less common in the aquarium hobby. It is based on a chemical reaction between bicarbonates or carbonates (baking soda, lime, potash, chalk, marble, eggshells, dolomite, etc.) and acids (acetic, hydrochloric, citric, etc.), in which carbon dioxide. In order to control the reaction rate and the volume of CO 2 released, the process is usually carried out in a rather complex unit called “ Kipp apparatus"(its classic laboratory version is shown in the figure), in which the reaction between solid carbonate and liquid acid can be finely controlled. The advantages of the method are the low cost of the starting components. The disadvantages are generally the same as those of the fermentation method: the difficulty of adjusting the process, the need to periodically change reagents (lime and acid are consumed), as well as the need for the same protective devices - a Drexel flask and a check valve - because chemical CO 2 is also capable of carrying away traces of acid and other harmful components, and backflow of aquarium water into the device can damage it.

Exotic ways

We will not dwell on them in detail, we will only say that they exist. This is the production of CO 2 using an electrolyzer, a powder generator, a TPV device, a hydrocarbonate thermoreactor, and other strange devices, the use of which in household aquarium keeping is not only difficult, but also, in the absence of skill, can be dangerous. Similar exotics should perhaps include “dry ice” (solid carbon dioxide) evaporators, which can lead to explosions and frostbite in the wrong hands. Among the industrial exotics, we can note those produced by some companies: pills to saturate water with carbon dioxide. Such tablets usually consist of calcium carbonate and dry organic acid, as well as retardants and mineral additives. When placed in an aquarium (or in a special device - a carbonator installed on the bottom), such tablets gradually dissolve, releasing CO 2 into the water. However, it is impossible to control this process, and their effectiveness raises reasonable doubts.

An example of such tablets:

Tablets for saturating water with carbon dioxide Hobby Sanoplant CO2 100 tablets
Tablets for saturating water with carbon dioxide Hobby Sanoplant CO2 20 tablets

What remains? Not the cheapest, but the most modern and reliable solution: supplying CO 2 from a cylinder...

Cylinder systems

Today, the most common and reliable are cylinder systems that supply CO 2 to the aquarium from disposable or reusable (refillable) gas cylinders.

Disposable cans, similar to aerosols, with a volume of 100 to 500 ml - a good solution for small aquariums. From such a canister, once a day, in the morning, a “bell” or “inverted cup” type reactor is filled with carbon dioxide (we will talk about the types of reactors below) and during the day this volume is gradually dissolved and used by plants. The gas in such a can lasts for about a month or two, depending on the intensity of use.

For very small nano-aquariums, CO 2 systems are produced with replaceable cartridges, similar to cans for old Soviet soda siphons or for pneumatic pistols, for example, these:

Much more common are reusable ones. refillable cylinders with reducer. In such cylinders with a capacity of 1 to 200 liters, CO 2 is in the form of a liquid under pressure. To supply gas from them to the aquarium, you need a two-stage reducer that reduces the pressure to a reasonable level. Usually it is equipped with two pressure gauges, one of which shows the pressure in the cylinder (and allows you to control how much carbon dioxide is left in it) and the second - the outlet pressure.

Reducer example:

Gas supply is regulated needle valve(fine adjustment tap) and special solenoid valve, usually included in aquarium CO 2 cylinder kits - they allow you to automate the regulation of gas supply, set daily regimes and turn off its supply at night (when there is no one to consume it anyway). You will definitely need it bubble counter(for what - we have already described above) and check valve, which prevents aquarium water from being sucked into the gearbox (which can easily be damaged by water).

CO 2 reactors, atomizers and diffusers

So, the method of generating CO 2 has been chosen (I hope that it is still a cylinder and not a “fermenter”!), accessories have been selected, and the final touch remains - how to supply CO 2 to the aquarium so that it dissolves in the water and does not erode from her into the room? Of course, conventional sprayers, with which we aerate water, are absolutely not suitable! With their help, we will saturate with gas not the aquarium, but the room in which it stands. Special devices are needed, which in the aquarium industry are collectively called “CO 2 reactors.” Let's start with the simplest ones.

"Bell" or "inverted cup". Actually, what it is is clear from the name. Usually this is a small plastic or glass container that is filled with water, placed in the aquarium with the open side down (attached to the wall using a suction cup) and filled with gas from a cylinder. During daylight hours, the gas from the cup gradually dissolves and is consumed, and in the evening the cup is filled again with water so that the operation can be repeated in the morning. This CO 2 reactor is only suitable for the smallest nano-aquariums, because its effectiveness is low. The main advantage of the “bell” is that with its help it is impossible to “overdo it” and create a concentration of CO 2 in the container that is dangerous for fish.

Wooden diffuser- hardwood sprayer (usually rowan, birch, willow or linden are used). Such a diffuser (unlike a conventional air spray) creates tiny gas bubbles that facilitate its dissolution. The advantage of such sprayers is simplicity combined with significant efficiency. Disadvantages are the need to supply gas under fairly high pressure (otherwise it is difficult to “push” such a stick), variable performance (the wood gradually swells and deteriorates) and fragility (replacement is needed every 2-3 months). You can make such a diffuser yourself, or you can buy a ready-made one:

Glass ceramic and membrane diffusers

This is the most common and diverse type of reactor for dissolving CO 2. What unites them all is the principle of operation: gas is supplied to a glass container located under water, the upper part of which is closed with a semi-permeable microporous glass disk, ceramic plate or plastic membrane. There are tiny holes in its surface through which the gas is slowly slowly pressed into the water in the form of tiny bubbles. The supply pressure is adjusted in such a way that there are few gas bubbles (and not as in the picture on the left!), and they would not reach the surface of the water, dissolving completely in its thickness.

Diffusers:

Another type of reactor is the so-called " bubble ladders". These are glass or plastic transparent labyrinths in which each bubble of CO 2, launched from below, gradually rises along steps or in a spiral, slowly passing through the water column and dissolving in it along the way. With the correct setting of the “ladder”, not a single bubble should to reach its last step, or to reach it so small that it has no chance of getting to the surface of the water. This thing may be cumbersome, but it usually does not need decoration, because watching the bubbles rising through the labyrinth itself is a spectacle. truly meditative! :-) There are a great variety of these ladders, in different shapes and sizes. Their advantage is not only the mesmerizing slow dance of bubbles, but also that they (unlike wooden and membrane diffusers) do not require excess gas pressure. , which allows them to be used together with “mash” type generators. They do not need a separate bubble counter - they can be easily counted with a stopwatch at the entrance to the reactor.

(The Aquatic Gardener 2007 vol. 20 (3) pp. 24-33, translation by Ruslan Ivanyushin, Tropica).

Answers the question:

Expert on cichlids and general aquarium maintenance

Hello! Tell me, is it possible to build a CO2 generator for an aquarium with your own hands? How effective are homemade installations? Or is it still worth purchasing a CO2 supply system from a specialized store?

The modern aquarium equipment market has a wide range of CO2 supply systems. However, the bulkiness and high cost of generators are confusing. That is why many aquarists solve the problem of supplying carbon dioxide to the reservoir on their own. Well, it’s quite understandable, because the “unit” for the production of CO2, made with one’s own hands, is quite effective and simple to implement. So, do-it-yourself CO2 reactor for an aquarium: step-by-step instructions.

Required:

2 liter transparent plastic bottle (main container for mash);
a plastic bottle with a wide neck (a kind of filter);
5 gram syringe (bubble counter);
a dropper, or rather, a hose from it (system connector);
aquarium silicone (sealant);
back pressure valve;
sprayer (although you can do without it);
triple adapter, taps (you can also get by);
aquarium hose or tube;
suction cups for fixing the hose.

Once all the necessary parts are ready, we begin assembly.

clean the lid from the partitions with a knife;
remove the plunger from the syringe and cut off the bottom part. Insert a back pressure valve into it and check if air flows through;
insert the syringe into the previously prepared cap. For greater reliability, treat the lid with silicone. Fill the syringe with water - the bubble counter is ready;
screw the resulting counter to a plastic two-liter bottle;
disconnect the adapter from the dropper. Throw away the feed regulator - we won't need it. Make a hole in the cap of a wide-necked bottle for the adapter. Next to it, use a needle from a dropper to make another hole;
Insert the hose from the dropper into the adapter at the bottom of the lid. Silicone the adapters on both sides and fill the filter with water;
connect the system using hoses from the dropper. The hose from the brew container should go to the filter valve, while the hose from the needle goes into the aquarium.

As for the mash itself, there are several recipes for its preparation. Below is the most popular.

An approximate diagram of assembling a CO2 reactor for an aquarium:

Recipe 1

pour sugar (150 g) into the mash jar;
add tea soda (on the tip of a knife);
sprinkle some fish food and plant fertilizer;
another small piece of bread (as an alternative - two raisins or dried apricots) and yeast (dry or “live”).

Fill the broth with boiled water, leaving 4 cm to the neck. Seal the generator tightly. Place the sprayer into the pond and wait for the results. By the way, you will have to wait from 8 to 12 hours. If the installation does not work after a day, check its tightness and add yeast and sugar. Braga “works” for 2-3 weeks. After which 2/3 is drained, the rest is refueled.

Effect on plant growth in the aquarium:

Recipe 2

sugar (40 tbsp);
soda (13 tbsp.);
starch (16 tbsp);
water (2 l.).

Cook the ingredients until thickened. Then cool and pour into a mash container. Efficiency - up to 3 months.

Recipe 3

sugar (150 gr.);
yeast (1 tsp);
soda (2 tsp);
flour (2 tbsp);
water (1.5 l.).

Working capacity - 1.5-2 weeks.

Recipe 4

gelatin (30 gr.);
soda (1 tbsp);
yeast (1 tsp);
sugar (3 cups);
water (1 l.).

Soak the gelatin in 0.5 liters of water for 40 minutes. Then add the rest of the water, add sugar and soda. Heat over low heat until the ingredients dissolve. Pour the solution into a brew container, and then add yeast. No need to stir. Efficiency - up to 1 month.

Recipe 5

sugar (5 tbsp);
starch (2 tbsp);
soda (1 tbsp);
yeast (1 tsp)
water (2 l.).

Dissolve starch, soda and sugar in water. Warm up in a water bath. Soak the yeast in a small amount of water and add to the mixture. Working capacity 3-4 weeks.

Table of optimal CO2 levels in an aquarium:

Video: DIY CO2 reactor for an aquarium:

Many people have a desire to have a pet. But not everyone has this opportunity. Some have allergies, while others do not have living conditions. In this case, you can put an aquarium in your house. There are many varieties of them, among which it is possible to choose one suitable for any conditions: large or small, of different geometric shapes, interesting design, built-in, etc.

In order for the life of the inhabitants of the aquarium to also be cozy and comfortable, the aquarium must be cleaned periodically

For some time after purchase, the appearance of the aquarium will be ideal and will please the eyes of the owners. But they have one common problem - any vessel, like its inhabitants, can be changed. To maintain beauty, special, and most importantly, constant care is required.

Basic rules of care

It is no secret that every aquarium owner wants to speed up the development of living creatures, the process of growth and reproduction of fish. Therefore, such people run to the store, buy various growth stimulants and other chemicals, and actively add them to the water. Unfortunately, no one remembers that interfering with natural processes can cause irreparable harm.

To survive, underwater creatures need oxygen and carbon, which are in short supply in water. Therefore, you need to purchase a pump that will guarantee cyclical air movement and allow algae and fish to breathe.

Air supply devices can be purchased at any pet store. But such devices have a high price. For those people who are not used to spending extra money, there is an excellent option for a system for supplying CO2 to an aquarium, made with your own hands using soda and citric acid. These substances react and saturate the water with carbon dioxide.

Why do underwater inhabitants need carbon?

Living organisms need CO2 gas to the same extent as oxygen. As is known, some of them have the ability to produce it independently, through the process of photosynthesis. But underwater inhabitants produce so little of this gas that the shortage can become almost critical.

What are the benefits of carbon dioxide? It performs several very important functions:

with a sufficient amount of CO2, algae develop correctly and quickly, have a bright green color;
additional production of oxygen is stimulated, which ensures the vital activity of aquatic inhabitants;
Many species of fish require a more acidic environment; by supplying gas, the pH of the water can be lowered.

Carbon dioxide alone is not enough for the life of organisms. Do not forget about sufficient lighting, the right temperature and the necessary fertilizing.

Economical, easy to manufacture and use, and most importantly safe CO2 generator

Ignoring even one of the listed elements can destroy the flora and fauna in the aquarium. When there is insufficient light, photosynthesis does not occur. Therefore, the power of lighting lamps must be selected in accordance with the size of the vessel. And high water temperature reduces the concentration of oxygen and CO2. From the facts brought up, it emerges that only correct and comprehensive care can be a guarantee of success.

Types of installations

Gas is supplied using special technologies. Is it possible to do without them? Of course it is possible, but not recommended. There are several types of such technologies:

mechanical or balloon installation (can only be bought in a store);
chemical;
homemade devices.

The simplest and most convenient to use is the mechanical method. After all, this is a purchased item with detailed instructions, but it is quite expensive. Buying such a device for one small home vessel is not entirely cost-effective.

Self-assembly procedure

Those hobbyists who cannot afford to buy such an expensive item use technologies based on chemical reactions. But it’s difficult to make these yourself, and store-bought ones need to be changed regularly. Therefore, a do-it-yourself installation with citric acid and soda is popular. The process of assembling this system is quite simple, especially since there are many instructions in video format on the Internet.

To increase the concentration of CO2 in the aquarium, a special installation is built; its operating principle is based on the interaction of citric acid and soda. You will need two plastic bottles, sixty grams of soda are poured into one container, and fifty grams of citric acid into the second. Add half a cup of water to each vessel. Shake the bottles to mix well, the substances should completely dissolve in the water.

When adding ingredients, strictly adhere to the proportions, otherwise the result will be unpredictable.

We close the plastic container with stoppers prepared in advance, which have a fitting and wiring. We connect the system to the aquarium. To start the process, you need to close the valve and press the bottle with the acid solution. After which the reaction of soda and citric acid will begin with the release of gas, the pressure in the vessels will increase. Once the pressure has stabilized, the system is ready for operation and production of CO2 for the aquarium.

The CO2 supply procedure using citric acid is stable and reliable. One refill lasts for two or three weeks. Thanks to the technology, the production of oxygen by algae is stimulated and, accordingly, faster growth and reproduction of fish occurs.