Stubborn algae can be caused by low chlorine levels, poor water circulation, or very warm weather. HTH Algae Guard+ Ultra is the strongest algae control formula from HTH, the brand swimming pool owners have trusted for over 90 years. The non-foaming non-staining formula both kills and prevents extreme amounts of stubborn green, black, and mustard algae for a season of crystal clear pool water. Simply add directly to your swimming pool water and nave right back in! HTH Algae Guard+ Ultra is compatible with all swimming pool types.
