Well after cycling my water it left the water a little lower than I like (not because it's dangerous or anything..it just doesn't look as good). My measurements for treating water only really works by the gallon, but I don't need to add that much. My question, then, is can I treat a gallon of water, let it sit for a while to treat all the water, and then just pour in about 1/4 a gallon? If that is possible, is it safe to put the 3/4 back and pour it in a week later when I do the next cycling?