'Pool Klear No.171' is an algaecide. Its Federal EPA registration number is: 11694-51. It was originally approved by EPA on 21 Mar 1975. Its registration got cancelled on 01 Jul 1987. It has a 'Caution' signal word. It has the following active ingredients: Poly(oxy-1,2-ethanediyl(dimethylimino)-1,2-ethanediyl(dimethylimino)-1,2-ethanediyl dichloride). It's approved for 1 sites including swimming pool water. It is also approved for 2 pests and pest groups including but not limited to algae and black algae.