I have a 75g FOWLR
tank that came with glass covers. The back 2" of the covers are plastic so that you can cut it around the equipment. At the moment I don't have a skimmer, and am running a canister filter with no sump. I also have a 750 gph
powerhead pointed toward the water surface. After reading this thread I am concerned about having my tank sealed off from air.
So the question is, how much air is enough air? If I were to drill holes in the back 2" of plastic in the cover, would that allow enough "fresh" air to be benificial? With this method I estimate that I have about 1/4 of that area open, or 24 sq. in. The total surface area of the top of the tank would be about 960 sq. in. So I really have about 2 1/2% open. Would this be enough, or do I need a lot more? My wife really likes the idea of having it covered, but I know with it totally sealed I am already seeing a drop in PH.
Thanks for all your help.