I don't know what the ingredients in the shock was I bought two bottles to see if it would help but I used it and tossed out the containers. I went back to bleach since then. I have been testing and shocking it once a day. The chlorine seems to be holding well. I was surprised at that since in the past I always had trouble holding shock level when I had a bad algae problem. I just checked it and it looks the same as it did 6 weeks ago. I will be going out to do my nightly duty of vacuuming and shocking. I have to go out of town so it's on it's on for a few days. I will put a couple of chlorine tablets in the floater and open it all the way to hopefully hold the chlorine level until I return.

vanman2501