Swimming pools require regular maintenance to keep the water looking attractive and safe for swimmers. A range of chemicals are commonly used to keep the water from growing mold, bacteria and other organisms, but a combination of chemicals and a possible air leak in a pool hose can combine to form a heavy foam on the water's surface. Additionally, algaecides often have ingredients that contribute to foaming in the pool.
Skim the foam off the top of the water with a pool net to immediately reduce the amount of foam in the pool.
Add an anti-foaming agent to the pool water according to package instructions. Anti-foamers work differently as far as how to apply and how much to use. When used correctly, they can greatly reduce foam.
Stop using algaecides containing dimethyl benzyl ammonium chloride since that will frequently cause foaming in pool water. Algaecides containing chelated copper or polymer should not foam as much.
Check hoses going into the filter and the pool itself. If you see bubbles coming out of a hose, it likely has a leak and will need to be sealed or replaced. Air bubbles from the leak can accumulate to create foam on the water's surface.
Add an enzyme cleaner to the pool, one designed for pool water. The enzymes will gradually eat away at materials in the water contributing to foaming problems.
Pour pool shock into the water according to container instructions to raise the chlorine level of the water temporarily. This can help reduce foaming. Avoid swimming in the water until the filter has removed enough of the shock to return chlorine to normal levels, which you can determine with a water testing kit.