Is the carbon dioxide in compressed gas systems dangerous ?
500 g of carbon dioxide are equivalent to 11.36 mol (1 mol of carbon dioxide weighs 44.01 g).
1 mol of an ideal gas occupies 22.4 l volume under normal conditions (normal air pressure and temperature), which means the following for 500 g of carbon dioxide:
11.36 x 22.4 l = 254.48 l.
A room of 20 m2 (4 m x 5 m) and a ceiling height of 2.5 m contains 50 m³ of air, which is 50,000 l.
Carbon dioxide is heavier than air and collects at the bottom under calm conditions. The gas would be 1.27 cm above the ground with 500 g of carbon dioxide.
Then, correspondingly, 4 times higher with 2 kg.
When the CO₂ is mixed with the air in the room, 254.48 l of carbon dioxide correspond to a concentration of 0.5 % of carbon dioxide with 50,000 l room volume of a room with a size of 20 m2 and a standard ceiling height, which is in the range of the maximum work place concentration for an 8-hour working day.
Accordingly, no excessive danger is associated with carbon dioxide compressed gas systems for aquariums.
Nevertheless, a few points should be observed when dealing with a compressed gas system:
1) Please be aware that the compressed gas cylinders must undergo a TÜV test regularly every 10 years.
2) Rusty cylinders, especially with rust near or on the bottom, should no longer be used, even if they have a valid TÜV mark.
3) Do not store the compressed gas cylinders in the sun, as this causes the internal pressure to rise. Normally, nothing will happen if you do, as the cylinders are constructed to withstand pressures up to 200 bar, but the bursting disk may burst, thereby causing all the gas to escape. In this case, do not touch the cylinder without hand protection, as the cylinder becomes very cold due to the drop in pressure.
Where did my algae come from?
Algae problems in an aquarium can never be traced to just one factor or general condition, and instead, are always the result of a combination of different factors, which include light, fertilization, water changes – specifically, how often and how much – feeding, fish population and, of course, the specific water parameters.
According to analyses that were performed over a course of a number of years, red algae, at least the common brush algae and beard algae, occur in descending order at the following parameters:
1) too little carbon dioxide (in relationship to 100 % of the measured tank); the pH level should be in the slightly acetic range, depending on the carbonate hardness, in every case.
2) elevated phosphate levels (over 90 %); phosphate limitation by means of JBL PhosEx ultra is often helpful here.
3) too little and too irregular fertilization (there should always be traces of iron at least).
4) insufficient water changes; a weekly water change of over 30 % is recommended for algae problems.
5) not enough fast-growing plants.
Can/May I also use auch compressed gas cylinders by other manufacturers?
The connections on reusable CO₂ systems are generally standardised so that they can be used with other cylinders, with the exception of a few cases.
However please note the following restrictions. Some larger-sized cylinders are not approved for non-stop operation with pressure reducers and you will lose your warranty claim if you use such systems.
JBL ProFlora m500, JBL ProFlora m2000, JBL ProFlora u500: Is my system broken if there is a rapid and marked drop in cylinder pressure towards the end of the charge?
The rapid drop in the cylinder pressure shortly before the end of the charge does not constitute grounds for complaint. It is normal and unavoidable from a technical standpoint.
Reason: The cylinder is filled approximately halfway with liquid carbon dioxide. You remove gaseous CO2 from the cylinder; the corresponding share of the liquid CO2 passes to the gaseous phase; the pressure remains constant. It isn’t until less CO2 passes from the liquid phase to the gaseous phase that the cylinder pressure begins to drop.
This means your system is functioning normally.
How do I know that my CO2 pressure gas cylinder still has gas in it?
The cylinder pressure of 50 – 60 bar, depending on the room temperature, remains constant until the cylinder is almost completely empty. The easiest method is to weigh your CO2 cylinder incl. bracket when it is completely empty. This way you will know the exact tare weight of your CO2 cylinder with its attachment parts at any time. If you forget it you can read the tare weight on the CO2 cylinder (stamp marking at the neck of the cylinder) and add 0.5 kg for the safety bracket. A full m500 CO2 cylinder with security bracket weighs according to that tare + 1 kg (0.5 kg bracket + 0.5 kg filling) – a m2000 tare + 2.5 kg (0.5 kg bracket + 2 kg filling).
A large amount of carbon dioxide always escapes all at once while the solenoid valve of JBL pH Control 12 V is being opened.
A slight excess pressure develops between the pressure reducer and the solenoid valve when the solenoid valve is turned off. It then escapes all at once when the valve is opened. This can be prevented by doing the following:
1) Select the shortest possible length for the hose connection between the pressure reducer and JBL pH Control 12 V.
2) Reduce the preset operating pressure of your pressure reducer.
After installing the JBL ProFlora compressed gas system, no CO2 enters the reactor. However, the cylinder pressure and working pressure displayed are in the proper range.
Please check whether the check valve (JBL SafeStop) is installed properly. It should be installed as the last element before the reactor and with the tip of the arrow pointing to the reactor (JBL Taifun).
How long does a 500 g filling of a compressed gas cylinder of a ProFlora CO2 system last?
A general answer to this question cannot be given, as that would require additional information such as the number of bubbles per minute, whether you use a night time switch-off and how long the CO2 is supplied each day.
The storage life of a filling can be calculated approximately in a simplified manner. A CO2 bubble contains approx. 0.125 mg CO2, which is for 20 bubbles per minute of withdrawal for 24 hours 3.6 g of carbon dioxide per day or a range of slightly less than 139 days for the 500 g cylinder.
With a night time switch-off and 12 hours of CO2 supply, the range is slightly under 278 days for the same number of bubbles.
The calculation of range is analogous for the 2 kg compressed gas cylinder.
What’s the best way to deal with brush and beard algae?
1. Increase the volume of water changed each week to about 30-50%.
2. Fertilise regularly after each water change, e.g. with JBL Ferropol.
3. If necessary add a daily dose of Ferropol 24.
4. If algae promoting nutrients (especially phosphate) are present in higher quantities, use e.g. JBL PhosEx ultra to keep them under control.
5. Most important is carbon dioxide. Beard and brush algae are always a sign that there is too little carbon dioxide in the water. If a CO2 system is in use, increase its dosage. Alternatively consider installing a CO2 system like JBL ProFlora u401 or m601.
6. Put in fast growing stem plants as nutrient competitors.
7. If there is strong current, reduce it slightly.
Is a special action necessary when using CO₂ compressed gas cylinders?
Please note two important points:
1) Cylinder: Reusable cylinders are TÜV tested and this is stamped on the cylinder. This test needs to be renewed every 10 years, with the bottom of the cylinder and the valve sealing and threaded joint being tested.
2) The carbon dioxide:
Depending on its concentration, carbon dioxide is harmful in the air.
The respiratory rate and pulse rate increase at a carbon dioxide concentration of 3-5%. Other symptoms are headaches, discomfort and ringing in the ears. Carbon dioxide concentrations of 8-10% and more cause these symptoms to become more pronounced. This may lead to cramps, fainting, apnoea and death from suffocation.
One 500 g cylinder contains 500 g CO2. This is equal to 11.36 mol (chemical substance amount unit). One mol of a gaseous substance has a volume of 22.414 l under normal conditions (273.15 K, 101325 Pa), so that 500 g of CO2 result in a volume of 254.7 l. CO2 is heavier than air, so that it collects on the ground. This corresponds to a CO2 height level in the range of 12.735 mm = 1.27 cm for a room of 20 m². If it is mixed completely with the air in a room of 20 m² and a height of 2.5 m (corresponds to 50,000 l), this corresponds to a maximum gas concentration of 0.5 volume %, which is well below the dangerous level.
Does the use of bubble stones and a strong current expel the important plant nutrient, CO2, from the water?
During aeration and/or when there is a strong current, a gas equilibrium is achieved between the ambient air and the water. As a result a corresponding but very low CO2 content occurs too. BUT this low CO2 content is far too low to for most aquarium plants to thrive. The aquarium owner is therefore dependent on an additional CO2 supply by a CO2 fertiliser system. The higher CO2 content this achieves is reduced or, as commonly referred to in aquatics, expelled by the aeration and strong current. Therefore well planted aquariums should only be slightly aerated at night, if required.