BIO-DEX CXDR 55 gal Drum Clearex 500. Just 2 oz of Clearex 500 treats 14,000 1 gals of water. It is especially effective after algae treatments, dust storms or other times the water gets cloudy or loses its sparkle. Clearex 500 is a professional strength product that is suitable for home use. It's hypoallergenic, non-carcinogenic, non-corrosive and non-flammable. It won't clog your pool or spa's filter and works effectively with all pool filtration systems. Clearex 500 is free of petroleum and is not an oil-based product.