Usually, users of swimming pools have to clean it often from various contaminants. You can use water, soap, or even some bleach. You can put a capful or two of bleach in a bucket or large sprayer and apply it to the concrete surface. Algae can damage the surface of the fountain and clog the pump, causing it to overheat and burn out.

Never use chlorine as an algae control or cleaning agent. Chlorine can damage the pump and the surface of the fountain. Use bleach wisely and according to proper equipment practices.