I think they are all about the same - there are cheaper ones, but with a fiberglass pool you need the better ones. I ususally look for something online that is on sale. Some of the good ones are Proteams Metal Magic, Metal Free, & Sequasol. There are more too, but I can't think of the names Right now I am using proteams metal magic and it works really well. This and Jack's Magic are my favorites so far.