Planted tank with sponge filter

[Zombill]

I have a 30 gal heavily planted tank. I'm currently using just a sponge filter with an air stone inside but the bubbles are causing a lot of surface agitation. Does anyone have any ideas how to stop this?

 

[aqua_chem]

This will only be a problem if you are injecting CO2. If you're not artificially increasing CO2 levels (with DIY CO2 or pressurized) then increasing surface aggitation can only increase your CO2 levels, and both the flora and the fauna will appreciate the increased O2.

 

[OBEYtheFISH]

This will only be a problem if you are injecting CO2. If you're not artificially increasing CO2 levels (with DIY CO2 or pressurized) then increasing surface aggitation can only increase your CO2 levels, and both the flora and the fauna will appreciate the increased O2.

So having injected co2 & and an airstone in there is good?