I have five tanks running, 75, 55, 48, 40, and 30 gallons. I am having trouble loosing too many fish in some of my tanks. I can't keep any Loach's alive more than a few days, have lost a 5" Angel after a week, a 5" Pleco, some 2" Pleco's, 4 Pitcus Catfish, and others over the last few weeks...