Oxidizer in an aquarium: what it is and how it works, we do it ourselves

What is and why do you need an oxidizer in an aquarium?

An oxidizer is a device that obtains oxygen from hydrogen peroxide and supplies it to the aquarium. They can replace a compressor for aeration, which also saturates the aquatic environment with this useful gas.

This is especially true for aquariums with a small surface or too dense vegetation. At night, overgrown algae actively absorb oxygen, and the fish may suffocate.

Did you know? A good natural indicator showing whether there is enough oxygen in the aquarium are snails.
When there is a lack of oxygen, they are found on aquatic plants or on walls. If there is enough of this gas, then the snails may be on stones or other decorations. The oxidizer consists of the following parts:

• glass container;
• plastic cover with holes;
• catalysts;
• base.

Now on sale you can find oxidizers for transporting fish, for aquariums of various sizes and even for ponds.

How does he work

The required volume of hydrogen peroxide is poured into a glass container. It also contains a catalyst that decomposes peroxide into water and oxygen. The container is closed with a lid and inserted into the base.

The resulting molecular oxygen begins to squeeze hydrogen peroxide out of the lid hole into the base of the device. Usually the base is made of unpainted ceramics, which in itself is also a catalyst, which means that the process of producing water and oxygen continues there.

Important! When purchasing an oxidizer, you should consider the volume of water and the ability of this device to serve them. Usually its performance and recommended containers are already indicated on the packaging.

The device is placed in the aquarium between the decorative elements, and the water begins to be enriched with the gas necessary for the fish. Periodically, it is taken out and filled with peroxide again.

OXIDATOR A for aquariums from 200 to 700 l

OXIDATOR is an autonomous and self-regulating device that supplies your aquarium with oxygen year-round without the use of hoses and electrical wires.

• Removes ammonia, nitrites, hydrogen sulfide, putrid and musty odors, bacterial film from the surface of water, stones, hoses, sponges, etc. around the clock.
• Suitable for Freshwater and Saltwater Aquarium
• Raises redox potential
• Reduces silt deposits and cloudiness
• Eliminates greening of water, destroys blue-green algae cells, prevents their reproduction
• Eliminates fish death from suffocation, allows fish and plants to breathe more intensively
• Continuously treats many fish diseases, intestinal blockage, bacterial film on the mucous membrane of the eyes, ulcers after severe infections, neutralizes skin and gill parasites. With a high concentration of dissolved active oxygen in water, the cysts of many bacteria and protozoa (ichthyophthyriasis, etc.) die, stopping the spread of the disease.

General issues regarding the use of aquarium OXIDITORS.

What concentration of solution should be used for aquariums? If the aquarium has a volume of less than 1000 liters, then use a 6% solution. To transport fish in bags, fill the OXIDATOR FTc with 19.9% ​​peroxide; for large marine aquariums (from 500 l), a 19.9% ​​peroxide solution is needed.

Can OXIDITOR destroy algae? However, OXIDITORS are devices that have proven their ability to successfully combat algae. With prolonged use of OXIDITORS, even the most persistent algae can be dealt with. A prerequisite for the destruction of algae is the removal of organic residues (uneaten food, dead leaves and plant stems, etc.) on which the algae feed.

Question: Can I use homemade hydrogen peroxide solutions? No, because you cannot know how much oxygen will enter the water. The use of unstabilized solutions can lead to ineffective operation of OXIDANTS due to a sharp decrease in the concentration of the solution during storage. An incorrectly prepared solution of high concentration will lead to the death of fish and plants. Don't skimp on the original hydrogen peroxide solution!

Question: How should spare solutions be stored? Bottles and canisters can only be stored in an upright position. From 1 liter of a 30% solution, 110 liters of oxygen gas are obtained. At a temperature of 25 °C, only 1% of oxygen can evaporate from an open bottle with such a solution per year. Calculations show that 1% of 110 liters is just over 1 liter! To avoid destruction of bottles or canisters, they must be closed only with special stoppers, allowing the released gas to freely escape into the atmosphere.

OXIDITORS - capabilities and principles of operation.

The operation of the OXIDATOR is based on the catalytic decomposition of hydrogen peroxide, controlled by ambient temperature. The higher the temperature of the water where the OXIDITOR is installed, the faster the peroxide decomposes and the more oxygen comes out. The OXIDATOR is simple and ingenious, because pure, not yet decomposed peroxide remains only in the device. Using pure peroxide WITHOUT OXIDATING agent is dangerous! If you simply throw a tablet of dry (dehydrated) peroxide or pour a peroxide solution directly into a body of water, the peroxide will gradually begin to break down, releasing water and oxygen. The water gradually mixes with the water of the reservoir. Throwing or pouring pure peroxide directly into a body of water is dangerous! Peroxide is twice as heavy as water and it immediately sinks to the bottom. Firstly, all the peroxide will not decompose immediately, but will burn, oxidize and poison the bottom layers close to it, plant roots and beneficial bacteria. Secondly, the acidity of the water immediately drops sharply, the reservoir will become acidic, and all living organisms will die. Therefore, the process of decomposition of peroxide into pure oxygen and water must be slow and controlled. The secret of OXIDITORS is simple - the catalyst is ceramics of a special composition, which completely, slowly and in doses, decomposes hydrogen peroxide into water (H2O) and active oxygen (O*). H2O2 — ceramic catalyst —> H2O + O*

Design and operation of the OXIDATOR.

OXIDITORS - devices that produce PURE ACTIVE oxygen always have an internal flask - a container filled with a solution of stabilized hydrogen peroxide. One or more catalysts are placed in the flask. The flask is closed with a lid; there are small holes in the lid. As the peroxide decomposes through these holes, the remaining peroxide is squeezed into the outer flask or ceramic base. These ceramic parts also serve as catalysts. The peroxide from them does not splash into the reservoir because it is heavier than water. The peroxide on the surface of the outer flask or ceramic base also decomposes and pure oxygen enters the reservoir, the smallest oxygen bubbles will come out of the OXIDATOR, dissolving almost immediately in the water. Only very few bubbles can be seen.

OXIDATOR is a self-regulating device.

How does the release of pure oxygen occur over a long period of time? The answer can be given by looking at the tiny ceramic piece found in the OXIDATOR container. This is a small catalyst that releases oxygen. The resulting gas creates excess pressure, and the solution is squeezed out drop by drop through a small hole in the stopper of the container flask. The amount of solution flowing out of the container does not depend on the size of the hole, but on the performance of the catalyst. If the catalyst works too actively, an excess of solution will be supplied to the water; if it does not work at full capacity, then the amount of solution will not be enough. The amount of oxygen introduced into water depends on:

• size and number of catalysts used;
• concentration of the solution used;
• water temperature.

For marine and large freshwater aquariums, larger ceramic catalysts are used, about 1 cm long. Doubling the number of catalysts doubles the oxygen yield, so you can increase the productivity of the OXIDATOR

Concentration of the solution used and water temperature.

When the temperature increases by 8 degrees, the oxygen output doubles, and when the temperature decreases, it decreases several times. Doubling the concentration of the solution quadruples the dosage. This is due to the fact that twice as much solution containing a double dose of oxygen is “squeezed” out of the container. A liter of 30% hydrogen peroxide solution will release a total of 156 grams of pure oxygen. This amount is enough to completely saturate 20,000 liters of water once. In warm water the operating time is much shorter than in cold water. The duration of operation of the OXIDATOR depends on:

• water temperature (see above);
• capacity of the container for the solution (the larger it is, the longer the device works, and vice versa);
• concentration of the peroxide solution (the higher it is, the less the device works, and vice versa);
• quantity and size of the catalyst (increasing the number of catalysts reduces the operating time, and vice versa

Anti-algae oxidizer.

OXIDATOR greatly increases the oxidation-reduction potential (redox potential) of water. This inhibits the development of algae, stops the conversion of relatively non-toxic nitrates (NO3) into toxic nitrites (NO2), and oxidizes the organic substances and decomposition products contained in the water to carbon dioxide (CO2). The more carbon dioxide dissolved in water, the lower the acidity level (pH). Carbon (C) is the most important nutrient contained in water in the form of carbon dioxide, carbonic acid (H2CO3) and calcium bicarbonate [Ca(HCO3)2]. It is important to remember! That higher plants use more easily absorbed carbon dioxide CO2, and undesirable algae in water consume carbon from calcium bicarbonate (hard water from wells and wells). Consequently, a large amount of carbon dioxide CO2 is beneficial to higher aquatic plants, and an excess of Ca(HCO3)2 is beneficial to algae. When creating a current or aeration, the concentration of carbon dioxide will tend to normal at a given temperature. In this case, 1 liter of water will contain only 0.5 mg of CO2; The pH in this case with a carbonate hardness of 10° will be about 8.9. This indicator is unfavorable for most fish. This can also happen when plants are actively growing, kept in bright light, and consuming large amounts of carbon dioxide. Fluctuations in pH can cause big problems, especially in a pond. Thus, during the day, as a result of assimilation (absorption of nutrients by plants), the amount of CO2 decreases, and in the dark, it increases as a result of the respiration of both animals and plants. Thus, in the morning you will get a pH of about 7.0, and in the evening - 10.0. This suggests that acidity (pH) depends on light, algae development and the method of oxygen supply, and not on the properties of the water.

Oxidant against fish suffocation.

OXIDIZER is most effective in clean aquarium water, since then all the oxygen is completely used for fish respiration and against parasites. The higher the water temperature in the aquarium, the more often the fish breathes and the greater its need for oxygen. Install an OXIDATOR corresponding to the volume of your aquarium; it will allow you to contain a larger number of fish. The presence of an OXIDATOR does not replace the compressor, but complements and insures its action in case of sudden power outages or temperature fluctuations. The OXIDATOR is especially important in aquariums with goldfish, since they are large and the fish’s need for oxygen is high. It is also advisable to install an OXIDATOR when introducing new fish or when gill parasites are suspected. In aquariums with problem fish (discus, rays, Tanganika cichlids, etc.) and in marine aquariums, it is better to install an OXIDATOR in the external filter system, which will ensure more uniform mixing of oxygen-enriched water. If your fish show signs of suffocation, immediately install the OXIDITOR in the aquarium and at the same time replace the water with fresh, settled water. To eliminate asphyxia in transport containers or packages, use FT or FTc OXIDITORS while simultaneously replacing the water and adding a liquid catalyst from the FT or FTc OXIDITORS kit (see INSTRUCTIONS for APPLICATION). A liter of 30% hydrogen peroxide solution will release a total of 156 grams of pure oxygen. This amount is enough to completely saturate 20,000 liters of water once. At a temperature of 25 degrees and one large catalyst, a liter of hydrogen peroxide solution per day will produce oxygen: with a 30% solution - 5000 mg; at 6% - 270 mg and at 3% - 65 mg.

Oxidant for the treatment and prevention of infections.

For the treatment and prevention of fish infections, use OXIDITOR in clean aquarium water, since then its action is most fully directed. Infections prevented by active oxygen OXIDANT:

• Ichthyophthyriosis (spot disease)
• Virulosis
• Saprolegniosis (fungal rot)
• Asphyxia (choking)

Infections weakened by active oxygen OXIDANT:

• Skin and gill flukes
• Helminoses (internal flukes)
• Inflammation of the swim bladder
• Bacterial cataracts
• Aeromonosis (rubella of cyprinids)
• Ulcers on the body of fish, injuries and lesions of fins
• Bacterial incompatibility of fish
• Oodiniosis

• Duration of work 100 - 200 liters 1 4 weeks 200 – 400 liters 2 2 weeks 400 – 600 liters 3 1.3 weeks

  If your aquarium has a capacity of up to 400 liters, and the two-week duration of operation of the OXIDATOR is too short for you (for example, you are going on vacation), you can use two OXIDATOR A, placing one catalyst in each of their containers. As a result, the duration of their operation before recharging will increase to four weeks.

  Made in Germany Warranty period - 1 year

Benefits of use

The oxidizer supplies molecular and activated oxygen to the aquatic environment and has a number of advantages:

• it does not need electricity and wire;
• noiselessness;
• activated oxygen inhibits pathogenic microflora (bacteria, fungi, protozoa), oxidizes decay products and nitrites, carrying out a unique biopurification of water;
• the ability to suppress pathogenic bacteria has a beneficial effect on the health of fish suffering from bacterial infections and improves the adaptation of new fish;
• the redox potential increases, which prevents the appearance and growth of algae.

Learn how to make an external filter, bottom filter, phytofilter, sump for an aquarium.

How to make an oxidizer for an aquarium with your own hands

In order to assemble this environmentally friendly device yourself, you need the following materials:

• ceramic unpainted container of small volume with a narrow neck - 1 pc.;
• champagne cork - 1 pc.;
• 3% hydrogen peroxide.

When making an oxidizer, the following steps should be performed:

1. Release the cork from the wire and cut a piece of the required size.

2. Use a sharp knife to adjust a piece of cork to the size of the neck of the selected vessel.

3. Take a drill of the smallest size and make a hole in the center of the cork.

   
   Moreover, the hole is not made completely with a drill, and then it is completed with a needle.

4. Hydrogen peroxide is poured into an unpainted ceramic container and tightly sealed with a stopper.

The resulting homemade oxidizer can already be placed in the aquarium.
If you have not found a suitable ceramic container, then you can take any other one and throw ceramic fragments or basalt aquarium soil into it as a catalyst. Learn how to make driftwood, artificial plants, and automatic feeders for your aquarium.

A small, beautiful container can become not only a homemade oxidizer, but also an additional decorative element.

To combat algae and bacterial diseases of fish, you need to take hydrogen peroxide with a higher concentration and an additional catalyst. For a more powerful catalysis process, pieces of baked clay can be used.

Do-it-yourself oxidizer for an aquarium: video

Important! When using a homemade oxidizer, you should measure the oxygen level with special testers (the norm is 5 mg/liter). If such measurements are not possible, then it is necessary to monitor the behavior of its inhabitants. When starved of oxygen, fish rise to the surface and begin to swallow water and then the air itself. Excess oxygen can cause gas embolism in fish, which manifests itself as red eyes, protruding scales and restless behavior.

DIY oxygen generators

Humanity's need for seafood is growing along with the population, and valuable fish species are at the limit of the maximum possible catch. Traditional fish farming requires abundant water resources.

Increasing pollution of the world's oceans is affecting the quality of seafood.

All this contributes to the popularity of RAS (recirculating water supply installations), which make it possible to grow environmentally friendly fish in a small amount of water.

RAS, which allow growing environmentally friendly fish, are gaining increasing popularity

Instructions for use and installation

Let's look at how purchased oxidizers are used for different volumes of water. The principle of operation of these devices: with an increase in the serviced volumes, the amount and concentration of hydrogen peroxide and the number of catalysts increase. If the inhabitants of the aquarium are large and nimble fish, then pebbles are used to fix the oxidizer.

Oxidator MINI

This version of the device is intended for aquariums no more than 60 liters. This universal oxidizing agent is good for long-term transportation of fish. It is placed in a vertical position at the bottom of a container of water.

The dimensions of the device are small: 6 cm high and 4 cm in diameter. Container for refilling hydrogen peroxide with a capacity of 20 ml. After emptying, it is refilled with stabilized peroxide.

The kit includes two 50 ml containers with a 4.9% hydrogen peroxide solution.

Operating period at a temperature of +25 °C:

• for volumes up to 30 liters, it is enough to take 1 catalyst, the operating time will be 28 days;
• for volumes in the range of 30–60 liters you need to take 2 catalysts. The working time in this case will be 14 days.

In large aquariums you can place up to four MINI oxidizers or change the catalysts to more effective ones.
The MINI oxidizer produces very small bubbles that are barely visible when the device is running. If there are no bubbles at all, then the container is empty and needs to be filled with solution.

Important! You should not use unstabilized or homemade solutions to fill the container - this can lead to the death of the inhabitants of the aquarium. Use only stabilized peroxide 4.9% and 6%.

Oxidator D

Designed for containers from 60 to 150 l. Dimensions: diameter - 8.5 cm, height - 8.5 cm. The capacity of the container for refilling with a 3-6% hydrogen peroxide solution is 125 ml. Duration of operation at a temperature of +25 °C - 1 liter of hydrogen peroxide is enough for 60 days.

Oxidant A

Suitable for large aquariums with a capacity of 150–400 liters. The operation of this device ensures a continuous supply of oxygen. For aquariums larger than 400 l (400–700 l), it is recommended to install two oxidizers A.

It is placed in a vertical position on the bottom of the aquarium. In a seawater aquarium, the device should be installed in an external filter. Its dimensions are: diameter - 9 cm, height - 18 cm. The capacity of the container for refilling with a 6% hydrogen peroxide solution is 250 ml.

Find out if it is possible not to settle your aquarium water.

The operating time at a temperature of +25 °C can last from 14 to 56 days. This value depends on the number of catalysts and the percentage of hydrogen peroxide. The absence of bubbles indicates that the peroxide container is empty.

The table shows the operating time of the device depending on the volume of water and catalysts.

Oxidator W

Used for significant volumes of water - 600 liters and above. It is placed in a vertical position at the bottom of the container. In a saltwater aquarium, place the device in an external filter or away from corals and sea anemones. Device parameters: diameter - 15 cm, height - 18 cm. The capacity of the container for refilling is 1 liter, and the concentration of the hydrogen peroxide solution used can be 6–30%.

The operating time at a temperature of +25 °C ranges from 14–56 days depending on the number of catalysts and the concentration of the solution. When bubbles stop coming out of the container, you need to refill it. The required volume of solution for refilling for one year is approximately 3 to 5 liters.

Find out why your aquarium water is green and cloudy.

A distinctive feature of the W oxidizer is its ability to produce large amounts of oxygen in a short period of time. It is recommended to use it for large containers with an installed filtration system.

For an aquatic environment with a volume of 600 to 2000 liters, you need to use 6% peroxide to fill the container. And for volumes from 2000 to 5000 liters you need to take peroxide 19.9%.

In open reservoirs (swimming pool, artificial pond, etc.) about 5000 liters and in external open biofilters of oceanariums, hydrogen peroxide is used with a concentration of 19.9 to 30%.

Did you know? The weather can be determined by the fish in the aquarium: when the atmospheric pressure decreases, they lose their appetite, rise to the water surface and swallow air. The reason for this behavior is that at low atmospheric pressure, the ability of gases to dissolve in water decreases, and aquatic inhabitants begin to experience oxygen deficiency.

Oxidizers are an excellent alternative to compressors for aeration. They not only saturate the aquarium environment with the oxygen the fish need. Activated oxygen released by hydrogen peroxide used in these devices inhibits pathogenic flora, oxidizes nitrites and decay products, and prevents the growth of algae.

On sale you can find oxidizers for various volumes of water, used not only in aquariums, but also in ponds, when transporting fish. This simple device can be assembled at home and refilled with ordinary hydrogen peroxide from a pharmacy.

Do-it-yourself oxygen generators - Metalist's Handbook

Dissolved oxygen (DO) availability is usually the main factor that limits the ability to increase stocking density in a closed water system. Its concentration is measured using various methods (more details).

Using only aeration to provide oxygen allows the planting density to be maintained at 40 kg/m3. However, the introduction of pure oxygen using efficient gas supply equipment increases the planting density to 120 kg/m3.

The difference in the concentration of dissolved oxygen at the inlet of the cultivation tank (10 mg/l with aeration or 18 mg/l supply of pure oxygen) and at the outlet of the system is taken into account.

For example, with a dissolved oxygen concentration at the outlet of 6 mg/l, only 4 mg/l is available for fish respiration during aeration (10 mg/l - 6 mg/l) and 12 mg/l when pure oxygen is supplied (18 mg/l - 6 mg/l). Thus, the planting density can increase from 40 kg/m3 to 120 kg/m3.

Interestingly, the concentration of by-products (solid sediment) also increases with increasing stocking density. Therefore, more efficient removal is necessary, for example, the use of a micro-mesh filter.

The demands of aquatic organisms for oxygen concentration depend on numerous factors, including stocking density, amount of food supplied, stress levels, water temperature and several others.

Cold-water species require 0.3-0.5 kg of oxygen per 1 kg of food. At high temperatures and the presence of oxygen demand from the biofilter and other bacteria, the need for oxygen increases to 1 kg of oxygen per 1 kg of feed.

Minimum dissolved oxygen values ​​also depend on the needs of the particular fish species and rearing conditions. Tilapia can survive dissolved oxygen levels that would kill rainbow trout or salmon within minutes.

It is worth noting that O2 concentrations less than 4-6 mg/l reduce growth rates.

Planting density can be increased by increasing the amount of feed applied when the problem of oxygen availability is solved and limiting factors such as the total level of nitrogen-containing products, CO2, and the volume of the cultivation tank are reduced. Increasing stocking density must be economically justified.

Thus, the concentration of dissolved oxygen is one of the most significant limiting factors determining the amount of fish produced.

However, intensification of the supply of pure oxygen to water, as well as aeration, is limited because for every 10 mg/l of O2 consumed, 1.0-1.4 mg/l TAN (total nitrogen level), 13-14 mg/ l CO2 and 10-20 mg/l solids in sediment. When the oxygen consumption of the system is more than 10-22 mg/l (depending on alkalinity, pH, temperature, fish species), the concentration of dissolved carbon dioxide becomes the limiting factor (without removing and controlling the pH).

Aeration with atmospheric air (left) and oxygenation with an oxygen mixture (right).

Transfer of gases

Aeration is the process of contact of gases with water.

When air comes into contact with water, the dissolved gases in the water reach an equilibrium phase, according to the partial pressure of the gases in the atmosphere. The dissolution of gases is influenced by two factors, the surface area of ​​the air-water interface and the difference in the partial pressures (concentrations) of gases at saturation and in water.

For example, if the water is not saturated with gas, the latter will dissolve. Otherwise, when the water becomes oversaturated, the gas will begin to leave the water. In the simplest drip column, supersaturated nitrogen can be removed from water, while oxygen that has not reached this state, on the contrary, begins to dissolve.

The rate of gas transfer depends on their deficiency (or excess) in solution. It is proportional to a constant known as the gas transfer coefficient. The overall gas transfer coefficient is determined by the conditions created with a particular gas supply system.

This is a composite indicator that includes factors such as gas diffusion coefficient, liquid film thickness and air-water interface area. The factors mentioned also indicate ways to increase the total amount of transported gas.

For example, it is possible to reduce the thickness of a liquid film by mixing and creating turbulent flows; by reducing the size of the bubbles, increase the surface area of ​​the air-water phase interface; or increase the concentration gradient.

The concentration gradient can be increased by introducing pure oxygen, installing high-pressure systems, and restraining the partial pressure of the gas in the atmosphere from sudden changes as it flows through the transfer system (increasing the interface area).

Pure oxygen comes into contact with water, where it reaches a supersaturated state. In this case, a small proportion of nitrogen leaves the solution.

Under normal aeration conditions, the planting density remains relatively low (less than 40 kg/m3), but contact of water with atmospheric air is ensured, which prevents the accumulation of toxic concentrations of carbon dioxide.

There are three oxygen sources most commonly used in fish farming: high-pressure mixed oxygen, liquefied oxygen, and on-site oxygen generation. To guarantee the presence of oxygen, many farms have at least two sources of oxygen.

An oxygen mixture under high pressure, contains from 3 to 7 m3 of gas under a pressure of 170 atmospheres. To increase capacity, several cylinders can be connected together.

Due to their high cost and limited capacity, oxygen cylinders are used only as a backup in case of emergency.

Oxygen can also be generated on site using pressure swing adsorption (PSA) or vacuum separation adsorption (VSA).

In both cases, a molecular microfilter is used to selectively adsorb or absorb nitrogen from the air to produce an oxygen-enriched mixture. There are models on the market with a capacity of 0.5-14 kg of oxygen per hour at 0.7-3.3 atmospheres.

To produce a mixture containing 85-95% oxygen, a source of dry, filtered air supplied at a pressure of 6.0-10.0 atmospheres is required. PSA and VSA operating units operate periodically and are activated only when necessary.

They are very reliable and do not require much maintenance. However, this equipment is very expensive, as is its operation, due to the need for high-pressure air supply.

In addition, since PSA and VSA units require electricity (1.1 kW per 1 kg O2) to operate, a backup source of pure oxygen is required in case of power failure.

Very often it is possible to obtain liquid oxygen of 98-99% purity, which can be transported and stored in containers such as a Dewar flask. At 1 atmosphere, liquid oxygen boils at -182.96°C, so a special cryogenic storage container is required.

It can vary in size from 0.11 m3 to 38 m3, and is usually rented or leased from suppliers, although smaller containers may be sold. Four and a half liters of liquid oxygen is equivalent to 3.26 m3 of gaseous oxygen.

The maximum pressure in the container varies from 8.775 to 11.7 atmospheres. Before use, liquid oxygen is evaporated directly through heat exchangers. The liquid oxygen storage system consists of a storage tank, a heat exchanger-gasifier and a pressure regulator.

The use of this equipment depends on transportation costs, and reduces the cost of maintaining and purchasing PSA systems. Equipment for storing and supplying liquid oxygen is very reliable and works even during a power outage.

Problems are observed when using it as a backup option in case of a power outage, when the stored volume of gas is not enough. It is necessary to carefully consider possible risks and select containers of sufficient volume.

There should be enough oxygen for at least 30 days of operation. At the first sign of deteriorating weather conditions and the use of a liquefied mixture, it is prudent to reduce the amount of feed introduced, which will reduce the oxygen demands of the fish over the next 24 hours.

Oxygenation equipment

In the continuous liquid phase (bubbles in water): U-shaped pipes, oxygen cones (saturation in a downward flow of water), oxygen aspirator, nebulizers.

To transfer oxygen, a continuous gas phase (water dripping in air) is used: multi-level low-pressure oxygenators, packaged or atomizing columns, pressurized columns, closed mechanical surface mixers.

Multi-level low-pressure oxygenators are most often used because they are designed for high-velocity flow with minimal hydrostatic head. The traditional low-pressure oxygenator was developed by Wotten in 1989.