Put this in a new pool and it immediately made the water nice. Using with a salt system and have not had to do anything to the pool since starting it up.Update 2020: Have added this in the spring and fall since building my pool and everyone comments about how sparkly my water is. We add well water with metals so without this my steps get that yellow denture look. Once my ph, salt and chlorine is right I do little but test the water. We have had killer heat for the past two summers with several months of 90+ days and algae bloom is not a problem if I keep up with my testing. I usually get lazy and have to do some extra work about once a summer. One of my granddaughters has skin issues but this product has no affect on her.