Green Water-Crystal Clear ALGAE OFF Algae-Off is a granular algaecide for water gardens and Koi ponds.  Immediate Algae Removal,Works on contact,EPA registered,Removes string algae Effective against green water,Removes odors,Adds oxygen,Works on non-painted surfaces,Water activated Dosage Rate:Can be found on the products more info page. Spot Treatment: Apply Algae-Off in a dry form over a wet surface. Wait 15-20  minutes, then rinse off. ALGAE-OFF 2-LB CRYSTAL CLEAR: ALGAE-OFF 2-LB $13.75 SKU: WIN82 Click here to save 5% off of your order! ALGAE-OFF 10-LB CRYSTAL CLEAR: ALGAE-OFF 10-LB $59.99 SKU: WIN83 Click here to save 5% off of your order!