We have a 75 gallon tank- running for about 3 weeks. It was set up using media & decorations from a previously established tank. Cascade 1000 canister filter, AquaClear 70 HOB filter, 2 150watt heaters & 2 large air stones. We have the following fish: 6 (3 albino, 3 green) cory cats, 2 rubber...