| | I Must Be Doing Something Right
I just read on advancedplantedtank.com that a 40 gallon aquarium, in their estimation, would use about 5 pounds of CO2 every 3 to 4 months. I just purchased a third 20 pound cylinder for my 410 gallon aquarium and the first 2 cylinders lasted an average of 4.6 months each! I realize that a lot of parameters go into CO2 usage but, according to the above estimate, it should take somewhere around 60 pounds for 4.6 months in my aquarium considering just the volume.
I have paid a lot of attention to flow rates and flow patterns of the water in my aquarium and done a lot to avoid off gassing. The outlets from the filter are below the surface and directed toward different depths. With outlets at each end of the tank I establish a circular flow pattern which I switch from clockwise to counterclockwise and then back once a week. This distributes the CO2 throughout the aquarium and also helps avoid detritus buildup. There is essentially no disturbance of the surface water in the aquarium but all of the water for my wet/dry is drawn from near the upper surface. The tops of the prefilters and the wet side of the wet/dry are not sealed but are covered pretty well. My CO2 reactor is very efficient in that I never even see the CO2 entering the aquarium it is so well dissolved. I got the impression that misting might be better but I don't understand why. My plants are pearling like crazy and multiplying and growing rapidly. On a scale of 1 to 4 they are mostly ones and twos so that is undoubtedly aiding my success but the aquarium's being 30 inches deep adds to the challenge.
My injection system also maintains the pH between 6.7 and 6.9 by automatically turning the pH flow on and off. So the CO2 level is consistently at a good level without waste or over dosing. My understanding is that, considering my water hardness, this pH level maintains a good CO2 concentration. The system I use is definitely pricey but considering the convenience and consistency of the function I consider it money well spent especially with a tank of this size. Part of the convenience is due to the fact that it does not use a bubble counter which necessitates a lot of readjusting but is, instead, electronic.
Forgive me if a lot of this sounded like bragging. I didn't intend to do that. I am pleased with what I have but it is also the result of a lot of research, hard work and experimentation. I am hopeful that some of you find that what I have to say is of some value to your applications.