if you have no fish in the qt then drain it..... qt shouldnt have gravel you want a bare bottom tank.... move the filter in the tank with the highest bio load.... wait 2 weeks until its seeded.... then when you are ready for new fish (dont get a whole lot at once) move the filter over and fill up the tank with new water. keep a eye on the tank you pulled the filter from for 2-3 days. keep a eye on the qt for week. after a month of the fish being fine.... move into your other tank and get new fish.
stocking slowly isnt a bad thing.
stocking slowly isnt a bad thing.