yeah Tom that's what I'm going to do. I put in a gallon of 12.5% and a bag of dichlor. I'm going to keep it around 5 or 6 for a while and I look every day to see if I got any more dead animals in there. I also tested some bleach my wife buys with a method Watermom gave the site (thanks Watermom), its only 4% but now I know what it is. ON THE BRIGHT SIDE I found Safeway has their brand for 3.25 a gallon and its 8.25 %. We don't have a Menards here so that's a find.