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.
JBL ProFlora m500: What is the range of a 500g CO₂ cylinder?
There is no general answer to this question, as we do not know what the desired number of bubbles for your aquarium are. One bubble contains approx. 0.125 mg CO₂, which corresponds to 4 million bubbles for a 500 g cylinder. At a consumption of 10 bubbles per minute (600 bubbles per hour), this corresponds to 6667 hours, which in turn corresponds to around 277 days or slightly longer than 9 months of an unchanged CO₂ supply.
Please note that this is a rough estimate and does not represent a guarantee about how many days you can actually get out of one compressed gas cylinder.
Does the pressure reducer JBL ProFlora u001 also fit on the disposable bottles from Dennerle ?
No, this is not possible, because the disposable bottles have a different thread to the pressure reducer JBL ProFlora u401.
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).
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.
Is a special action necessary when using CO₂ compressed gas cylinders?
You must observe two points:
1) Cylinder: Reusable cylinders are TÜV tested and this is stamped on the cylinder. This test must 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. From: http://www-organik.chemie.uni-wuerzburg.de/misc/betr_ein/uw-g15.html : 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.
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 the 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 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.
Does the use of bubble stones and a strong current expel the important plant nutrient, CO2, from the water?
A bubble stone does NOT expel CO2 from the water. This is a widespread misconception in the hobby! CO2 and O2 are not related to each other in the water. Depending on the degree of saturation and the partial pressure gradient, they dissolve into air. Please bear in mind that we do not add pure oxygen to the aquarium, and instead add an air mixture of nitrogen, CO2, O2 and other components. When air pumps are used for ventilation, there is only an expulsion effect as a result of the enlarged surface of air/water if CO2 is added, to the effect that the partial pressure in the water is higher than in the air. This cannot be quantified without expending significant time and effort on metrology.