Varig8

I am using Hagans CO2 system. I have 2 of them in a 20L. I change them every 2 weeks as they just get slower and slower by that time. The plants seem to be doing fine, but Im afraid somehow this might affect my shrimp. Any suggestions or info is appreciated!

Squawkbert

It's pretty tough to OD w/ yeast driven CO2 systems. I'd stagger the pair though, changing them on alternate weeks (or alternate 2 weeks).