Things You'll Need
Chelated copper algaecide
If you are subject to water regulations that could prevent you from refilling a drained pool, try partially draining the pool and scrubbing as much of the exposed area as possible.
If your pool or hot tub has scummy, discolored foam on the surface, then you likely have an algaecide foam problem. While you may think that this is just something that you have to live with in order to keep your water clean, in reality, you can keep your water clear of algae without sacrificing the aesthetic value of your pool or clogging up your filters, which this foam can also do. It will take a little time to get the job done, but you can get rid of algaecide foam.
Drain the water from the pool or hot tub. As long as the algaecide is in the water, you will have some foam issues. As a result, you must remove the treated water.
Clean out the pool. Use the scrub brush, the cleanser, the vinegar and the bleach to scrub away any algae in the pool. Even on clear parts of the pool, scrub aggressively because you also need to remove traces of your foaming algaecide from the pool to as great an extent as possible.
Refill the pool. There should not be any new foam, since algaecides tend to cause scummy, thin foam and you have removed much of the algaecide and treated water.
Shock the pool. This will help prevent new algae growth. In most cases, it should be sufficient to prevent algae without the use of a new algaecide.
Use a chelated copper algaecide, which does not create foam, if you continue to experience problems with algae.