Hi..

35-42 ppm CO2 = 35-42 mg/l is to much.
15-20 ppm CO2 were o.K.
What does anyone think?
I think fish is the decisive factor.
30 ppm seems to be the norm these days, many people run much higher without
any ill effects.
^^
That sentence makes me feel becoming old..! ;-)

I keep mine around 35 ppm, which seems OK.

http://www.google.com/url?sa=D&q=htt...f/mckenzie.PDF

http://www.google.com/url?sa=D&q=htt...pBiol03-DM.pdf

http://www.google.com/url?sa=D&q=htt...l/Brauner1.pdf

I get too much growth for my liking actually.

Really? :-)

Not to mention too many large fish for a 15 gallon.

I agree with you.
--
cu
Marco