There are two types of Cal- hypo tabs: encased and solid. The encased ones are in plastic tube with holes in it. I've never had a chance to use them but I did have the others once. They were dreadful, turning to mush and clogging my skimmer in about a day. If you do use a floater, do NOT use one that has had Tri-chlor in it. Potentially dangerous. Buy a new one because they are usually cheap enough, around $10.