Hmm I am not sure on my GPH
or even how to figure that out. I know that I have an algea problem but I don't know if it is a big problem or not. I clean the glass almost every day to every two days because algea has grown again, and there is some on the rocks but the coral beauty eats a lot of that. I don't know about the O2
I figure if it was on oxygen problem they would be trying to get air near the top of the tank, but they stay at the very bottom behind the rocks. My Coral beauty is about 2.5-3 inches, 1 clown is 1 inch and the other is 1.5 inches. I use tap water, and I add a water conditioner that removes ammonia chlorine and Chloramine from the water. After the water change I did yesterday there doesn't seem to be any change at all better or worse. I really don't know if anything is wrong at all but the fast breathing was my first concern.