I never have treated my tap water before water changes and my tap water is near perfect with 0 ammonia, nitrite, and nitrate and very minimal chlorine. I dose with seachem safe before and a tiny bit after just in case and in the 5 years I've been running aquariums I've never had a problem pumping water straight from the tap into the aquarium. The reason for this thread is for ideas on what to do with the empty second chamber of my sump. The system is probably upwards of 100 gallons and doing a standard drain and fill for an hour and a half is out of the question