CO2 and surface agitation
I was browsing through Tropical Paradise book looking at those magnificent pictures of tanks. I find most of them are using canister filter with return that creates surface turbulence to one end of the tank.
I have been told to make as less surface agitation as possible to keep CO2 in, which seems to contradict with those tanks in the pics.
I have a 10G that was having surface scum buildup problem since day 1. For the past few weeks, I took out HOB whisper filter that pours water down to the surface. For the last few weeks, my CO2 level has noticeably gone up, and I was able to maintain pH of 6.6, kH of 5 degrees.
Last night, I decided to put the whisper back on. After just 12 hours, My pH has risen back up to 7.1. Aaaaaaargh~!
1. Oily surface bothers me. Should I keep whisper on?
2. Would installing a canister, having the return water creating mid-tank flow help out with surface scum problem?
3. For those that has surface agitation but are able to keep CO2 in, what did you do to achieve this?
4. When I am not using whisper, My CO2 level with the equation comes out to be 37ppm with pH 6.6 KH 5. At this level, I noticed cardinals breathing rapidly. I assume it has to do with high level of CO2 in the tank. Should I bring the CO2 level down to below 30ppm?