If you want to prevent or eliminate algae, remove one of it's most significant food sources: phosphates! 

PhosFree® is not an algicide or algistat. 

PhosFree® contains a rare mineral called lanthanum that when added to your swimming pool through the skimmer causes a thin film on your pool's filter media (sand, DE or Cartridge) which then physically removes phosphates from the water.

Effective with phosphate levels under 1000 ppb.

To learn more about phosphates, click here.

Excellent for use in pools with attached spas or fountains. 

For POOL use only.  DO NOT use in spas or hot tubs.

Application:
Read & follow all label instructions. Adjust chlorine to 1.0--3.0 ppm & balance water. Initially: 0.5 liter per 10,000 gallons for phosphate levels up to 300 ppb. Pump must run 48 hours for best results

Size Available:
2 liter bottle, $22.99 each