HTH Pool Care Algae Guard Ultra is the strongest algaecide formula available from the brand pool owners have trusted for over 25 years. Algae Guard Ultra both kills and prevents even the most stubborn green, black and mustard algae. This non-foaming algae guard treats pool water for up to 90 days after applying to your pool.
Long-lasting all algae eliminator
Eliminates and prevents green, black and mustard algae