CO2 mist and possible changes


Lifetime Members
Lifetime Member
Dec 16, 2009
Rice Lake, WI
I have a 6' long 125g that is currently filtered with 2 Ehiem 2075 E3's. I have a spray bar for the out feed of each of them just below the water line pointed down slightly, and Cal Aqua Lab inline diffusor for each one. Only a couple of weeks into my setup, but so far the results seem good. HC, Glosso, etc all growing very well. The only thing not growing well is a couple of the Hygro species, but they were emmersed and might still be acclimating, but not sure. The only problem I see is the CO2 mist. I currently have the CO2 hooked up to a solenoid valve/pH monitor and run it that way. It's on for a while, then off, etc as needed determined by the pH. I then use 2 drop checkers to get an idea where CO2 is at. One with 4kh and one with 5kh.

It seems like I've read a couple of different theories on mist versus fully (or virtually) dissolved CO2. Is there really a difference or are they both acceptable for good long-term setups? The bubbles I have are truly what I would call a mist and very tiny, but with both spray bars shooting them out it does create quite the scene. The mist doesn't really bother me all that much as I'm much more concerned with the results, but the mist does tend to collect on certain leaves more than others (Cabomba is a great example) and can cause them to break loose often.

I was thinking of building a Cerges reactor and trying that on one of the Eheims to see the result. Could I use the Cal Aqua Diffusor and then run the mist into the Cerges and then into the tank? Would that make any difference or would the result be only minimal improvement? If so, is it best to put bio balls into the Cerges?


Lifetime Members
Lifetime Member
Jan 10, 2010
Boca Raton, FL
I prefer CPR Bio Bale instead of bio balls. More square inches and easier to clean, plus greater surface area.