Algaecides are excellent treatments to prevent or kill algae growth when used with chlorine. As a preventative, algaecides act as an insurance policy in you pool, killing algae spores as they enter the water. Algae spores are constantly entering your pool from rain, wind and dust storms and they multiply rapidly in sunlight and warm water. Routine chlorination cannot, at times, cope with the rapid growth of an algae "bloom", the visible outburst of algae. These algae can appear green, brown, black, mustard or even pink in color.
By the time algae has bloomed there millions of algae cells in every gallon of water!