This product is a potent algaecide, which is effective against all algae when used as directed
It is especially effective against black algae which appears as spots on the walls and bottom of pools
Check pH of water. Adjust pH (if necessary) to a residual of 7.2-7.6 using a reliable test kit and AQUA GUARD™ pH UP (soda ash) or AQUA GUARD™ pH DOWN (dry pool acid)
Similarly, check available chlorine and adjust (if necessary) to a residual of 1.0-1.5 ppm using a dry or liquid chlorinating product (AQUA GUARD™ CHLORINATING LIQUID, AQUA GUARD™ ALL-IN-ONE CHLORINATING GRANULES, AQUA GUARD™ SHOCK QUICK or AQUA GUARD™ SUPER SHOCK QUICK)
Place one tablespoon of AQUA GUARD™ BLACK ALGAE TREATMENT directly on the black spots (if on the pool bottom). If spots are on the pool walls, place a tablespoon of AQUA GUARD™ BLACK ALGAE TREATMENT on a 6" square cloth, tie and hang from the edge of the pool by the spot
Wait 24 to 36 hours. Brush spots off with a wire algae brush and repeat steps until algae free
NOTE: Do not allow direct contact of this product on the following pool surfaces: vinyl, metallic, fiberglass, painted or colored plaster. Product will bleach color out.