SeaKlear 90-Day Algae Prevention & Remover only requires application once every 3 months to control algae. After application of this product, SeaKlear promises your pool water will sparkle like never before. This product is effective against the likes of blue-green, black, and mustard algae. It is also formulated to be non-staining. 90-Day Algae Prevention & Remover is an excellent broad-spectrum algaecide with a long-term residual effect in the pool. It is based on a unique, low-dose organic copper complex, which is extremely effective and economical.