My DIY mixture is ~2 cups of cheap, granulated sugar and 1/2 to 3/4 tsp of yeast. I replace the 2L bottles once every 3 weeks. And I rotate the bottles so that I replace one, then the other the next week, then I have a week off, repeat. Going into the Eheim I usually see about 1 to 3 bubbles per seconds, and I have little-to-no other agitation in the tank. I like to keep my KH high at about 12 to prevent huge pH swings that I would get when the CO2 gets really going. In the morning I see a pH of about 6.8, and it get down to about 6.6-6.7 towards the evening. Once the air stone kicks on, the pH jumps to about 7.0 to 7.1, maybe higher but I am usually asleep by this time. I should also mention that I just moved to Yuma, AZ, and my house temps are in the mid-80s. I'm sure the higher temps here versus in San Diego are causing the yeast to grow faster.
I'm due to change one of the bottles this weekend. I'll try to reduce the amount of yeast in the bottle and see what I get there. I guess anything that reduces my bubbles per minute will reduce my CO2 concentration.
I'd think about using the air stone during the photoperiod, but it really knocks the concentration way down.
Well, I think I have some ideas. At least enough to get me started. Thanks amigos.
-Dustin |