Hi Kramer. You'll need to provide us with a current set of water testing results taken with a drops-based kit for someone to be able to help. If you don't have a good test kit, you need one. The best one you can buy is the Taylor K-2006 or 2006C which you can get through the Amazon link in my signature below.
A floater filled with trichlor tabs is not going to take your chlorine level high enough to attack algae. Once we see some testing results, someone can better advise you. Also, tell us more about your pool.
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