I didnt use water from DT because it was at the end of cycle. but now that all levels amm., nitrite, and nitrate are at 0 i started doing 2 gal water changes to qt tank using water from dt and discarding water from qt. I am running a HOB bio wheel without the carbon filter due to copper treatment that i started. I have 2 small ocellaris clowns and a small 6 line in the 10 gal qt. clowns are doing great 6 line is hiding between piece of pvc and base of heater and isnt in terrible shape but not the greatest either. I am assuming it is due to the ammonia because when i put them all in there they were fine.