while i was doing hypo i would switch out a piece of rock here and there just to keep things stable, although the bacteria can survive hypo 100% all the food the rock houses like pods , coraline etc. will perish so if you have say a scooter or wrasses like i do then it helps to add a fresh food source back to them.
also not all fish can be hypo'd some do not do well like leopards,mandarins, sand sifters etc.
good luck friend
