i have heard that to keep the blue ball value at about 2oclock as with the air flow rate if i put to much water through i start getting a grrrrrrr grrrrrr sound
mine is the AP701 really happy with it. its on a direct flow T off with ball values going to the sump
at the moment i am ok but there are fish out there that i really like but cant get because of corals, not that i have any, so its hard do i get corals or get my fish then corals