I need a fish freshwater aquarium expert please?

do not use ANYTHING to clean out the tank. however, if you really must I have a trick for you. use clorox (no im not crazy) give it a week to evaporate. if you cant smell it, its not there anymore. then, if youre still scared, add dechlor. I cleaned out my 220 gallon aquarium with almost a gallon of clorox, and didnt even add dechlor, but all my fish are fine. the trick is to let it evaporate. good luck!