I am emptying my Discus tank in a week or 2, my lfs will hold my Discus for me, so while its being emptied and cleaned and refilled, i have a small empty tank which i am thinking of just running my external filters into so as to keep bacteria so dont have to cycle again. Question is do i need to add ammonia to keep bacteria fed or will just running them in freshwater be ok? It will be for about 2 days.