Good fertilization is essential in an aquarium for healthy and beautiful plant growth. The do-it-yourselfers make do with a self-made system, but this involves weekly maintenance. One of the most maintenance-free systems is the connection of a ready-to-use CO² bottle. Various parts are required for this. This system can last for just under 200 ?? installed and can be expanded afterwards.
Required parts for an automatic system
- A full refillable co₂ bottle;
- A double pressure gauge with needle valve;
- A solenoid valve;
- A non-return valve;
- A co₂ slang;
- A co₂ difussor;
- A timer switch.
The co₂ bottle
A co₂ bottle is available at various places. Important with such a bottle is the fact that it is inspected (In Germany this is called TUV inspection, in the Netherlands Stoomwezen is responsible for the inspection) Such an inspection is valid for 10 years in the case of carbon dioxide. The validity depends on the origin of the gas. Without an inspection, a bottle may not be refilled for safety. At the top of the bottle is a rotary knob, this is called the cylinder valve. The protruding piece of metal is the inlet piece.
The pressure gauges and the regulator
A pressure regulator is needed to bring the pressure of the bottle to a usable level. This must have an ISO 2503 certificate. This certificate ensures that the meter can be used for co₂ gas. A reducing device consists of a single-stage reducer or a dual-stage reducer. In this case, a dual-stage reducer is used. There are 2 pressure gauges on the regulator, which are available with single or double Bourdon pressure gauge. A double pressure gauge is the most comprehensive, but also the most expensive solution. The regulator ensures that no overpressure is created when the bottle is almost empty. This reducer has 2 Bourdon meters on which 2 values can be read. The first meter is called the content manometer, on which the internal pressure of the bottle can be read, which is expressed in bar. When this number drops to 0, the bottle is empty. The other meter is the working pressure gauge, which shows the working pressure. Its pressure is expressed in PSI or Bar. 1 bar is 14.5 PSI
There are 3 rotary knobs on the regulator. One button is used to open the bottle, the other is to regulate the operating pressure. Finally, this device has a needle valve, with which the number of drops of co₂ per minute is adjusted by means of a screw.
The solenoid valve aka solenoid valve
The plants in the aquarium consume co₂ during the day, but they release it themselves at night. If a co₂ system is left open, it can cause fish and other living things to be poisoned and die. This is where the solenoid valve comes in handy.
This piece of electronics cuts off the flow of the co₂ when the power is off. This is where the timer comes into play. The easiest way is to set the timer to the same hours as the aquarium lighting, so that the carbon dioxide supply is turned off at the appropriate time of the day. This ensures that this system requires little maintenance as this is automatic. A ph-controlled controller can be connected to this if necessary.
The check valve
This small piece of technology has a cover which ensures that only one-way traffic is possible. This prevents the aquarium from running back into the hose and then emptying over the floor. A small but important piece! Since the system works with an internal cover that can only open to one side, it is important that this piece is placed in the correct direction. Most check valves have an arrow to indicate the direction. If this is missing, blow through the valve for a moment, it will immediately become clear which side allows the air to pass through.
CO₂ hose
Carbon dioxide is a sour gas. To prevent that the transport hose is or will be porous, it is made of a material that is not broken down by co door. The internal diameter of such a hose is usually 4 mm, the external diameter 6 mm.
CO₂ diffuser
There are various systems on the market to dissolve the co₂ droplets, the most commonly used are:
- co₂ ladder;
- diffuser;
- atomizer;
- reactor.
This system uses a diffuser. The carbon dioxide droplets are divided into hundreds of tiny droplets by means of a fine-meshed stone. A drop counter is already built into this diffuser. However, this is not the case with all diffusers, a drop counter can also be purchased separately. Fill the stem of the diffuser 80% with water to count the drops. This device should be close to the filter outlet of the aquarium, this ensures optimal circulation of the bubbles throughout the aquarium. Gas has the characteristic of going up vertically, which means that the absorption by the water is lower. An unnecessary loss of co₂.
Connecting and testing the system
Turn the pressure gauge on the carbon dioxide bottle, make sure that the sealing ring is between these 2 parts. Tighten it with a wrench. Place a small piece of co₂ hose on the manometer, this will be the solenoid valve. Now again a small piece of co₂ hose is placed on the solenoid valve. After this comes the check valve, again followed by the rest of the hose. At the end of the hose is the diffuser that will hang in the aquarium.
To test the parts for leaks, lubricate all connectors with soapy water. Open the bottle gently, the pressure gauge must not enter the red zone! If bubbles form on the couplings, there is a leak in the system. Close the bottle. Check and tighten the connection and try again. If the leak continues, special tape can be applied to the relevant connection.
If there are no visible flavors, open the bottle until the content meter of the bottle reaches 50 to 60 bar. Now turn the fine adjustment valve until the operating pressure is 0.6 to 1 bar. Now close the bottle and see if the pressure on the bottle remains the same for a while. If this is the case, the system is almost certainly leak-free.
Now you can start fine-tuning the system. Open the bottle again and adjust the number of bubbles per minute using the fine adjustment screw. It may take some time at first for the diffuser to contain enough gas and pressure to operate. Start with 5 bubbles per 100 liters of water per minute. For the first few days, keep a close eye on the system as temperature changes and other factors can cause the adjustment to fail. Then increase the co₂ supply step by step until the desired amount of co₂ is in the aquarium.
Hints and tips
- Check the amount of CO in the aquarium with a test kit. Do this at different times of the day at the beginning to avoid poisoning. If the values remain stable and the amount of carbon dioxide is sufficient, then a little less can be measured.
- Make sure that all parts that are purchased have the same diameter in terms of connection. This prevents the purchase of additional coupling pieces. The more couplings, the greater the risk of leaks.
- If there is no co₂ flow into the aquarium and everything is set correctly and leak-free, try to make the pieces of co₂ hose between the different parts as short as possible.
- For this manual we used a CO₂ system which was ordered from aquaristic.net