I've been on here for awhile now and the obvious concensus is that the store-bought chemicals are mostly no good for the pool (tabs, bagged shock, etc.) and that bleach is far better for regulating chlorine. Why exactly is this? For years before I found this forum I was using HTH dual action tabs and HTH bagged shock, along with their pH plus and alkalinity plus, and I never had problems. Why are these chemicals so bad, and what damage can they do (I understand they may contain "fillers" and metals and whatever, but why is this bad?) I'm not trying to start an arguement, just learn a thing or two, God knows the bleach worked for me when my pool was a swamp!