If you buy the powder make sure you mix it according to the directions. Put the water in FIRST!!! I put the powder in not paying attention to the directions and it got very hot. It caused a hairline crack in my jugs (yes both of them). Unfortunately it dropped slowly and I did not realize it. The problem was it dripped right in my tank since it sat on a wire shelf above the sump in a closet. I dosed almost a third of my two part in two days before I noticed it. Yes, ti's true. i do stupid things sometimes and I am a typical man; I rarely read directions though I would normally benefit from it.