i dont really have the room to let the water decloranate, the stuff said safe for water gardens or ponds, but also says dont use on fish your gonna eat. as for the h202 the first week i started i got a mold problem that took 2 months to fully kill, i was hoping i could drop in a few ml of declorinator and some h2o2 at res change to eliminate a step and not have to worry as much. also i read some where a lot of citys use this other stuff instead of chlorine that stays in water forever