I had similar results when I went with a mist system. I was sure I was really pushing the maximum bubble rate for the CO2. But, when I got my little ADA style drop checker I found I needed quite a bit more CO2 to get to 30ppm, and now use 40 ppm with no fish distress. That helped a lot with BBA, but I still get some. Once I get my tank all cleaned up again from the GDA, I will try using 45 ppm of CO2 to see how that works out. Right now I have finished cleaning up the GDA film, cleaning the filter, 2 big water changes, cleaning up what BBA I found, and am now starting a three day blackout to see what that does.
Hi VaughnH, do you mind to explain how do I tell how much PPM of CO2 I have in my tank? If I have the pH, KH reading & the pH-KH chart, how do I proceed from here to determine the amount of CO2? A reference to exising related threads will help. Thanks in advance.
Our tanks do not have perfect water in them - they have other sources of alkalinity and acidity besides CO2 and carbonates. So, the pH/KH/CO2 chart or equation isn't reliable. If you use one of the ADA style "drop checkers" ( see DIY Drop Checker - Aquatic Plant Central- aquascaping...a living art) for more information, you can measure the CO2 in the tank with some accuracy. These little devices work because you can use distilled water, with a bit of sodium bicarbonate in it to get a 4 dKH sample of water that is "perfect" for calculating ppm of CO2 using a chart or calculator, such as Measuring CO2 levels in a Planted Tank. Quite a few people have now started using these devices and, so far, no one has refuted the claim that they really do work well.