Green algae is a common problem in above ground swimming pools. The algae tends to be the worst when first opening the pool for the swimming season. This is due to the above ground pool water sitting all winter without being circulated or treated properly. It's important to tackle the algae properly to ensure it does not come back in a few days. Algaecide and chlorine are used to combat algae, and can be purchased at local pool stores. Once you remove and treat the algae in the swimming pool, maintaining the clean, clear water simply consists of adding chlorine regularly and running the above ground pool filtration system.
Clear stuck-on algae and debris from the pool floor and sidewall of the above ground pool using the vacuum brush. This will make vacuuming the algae and dirt easier.
Dry your hands, and turn the pool filtration system on; it should be located outside the above ground pool near the skimmer. Hook up the vacuum per the vacuum manufacturer's instructions.
Vacuum the pool until all algae and dirt are picked up off the pool floor. The water will be murky and dirty from the algae.
Clean the pool skimmer and pool filter. Remove the basket from the pool skimmer, and empty it. Open the waste line on the pool filter and allow the water to run until it is clean. Close the waste line.
Add a gallon of algaecide and the appropriate amount of chlorine needed, based on the size of your above ground swimming pool. The amount needed is printed on the bottle of chlorine. Allow the pool filtration system to run until the water is clear and blue.