For example, general cleaning of an outdoor pool is done once a year, and a closed one - 3 times or more. Before this, the water is preliminarily drained. Different products are used to clean the surface. The choice of substance depends on the material used to make the bowl. You can of course do the cleaning yourself. But it is better to contact a specialized company. If the surface of the pool is tiled, then in this case you will need to apply enough force to give it its original appearance.