Products › PENTAIR 18 INCH STAINLESS STEEL ALGAE BRUSH Image 1 of 1 PENTAIR 18 INCH STAINLESS STEEL ALGAE BRUSH $67.33 18 inch metal back brush with stainless steel bristles for algae on plaster and concrete pools. Add To Cart Added! 18 inch metal back brush with stainless steel bristles for algae on plaster and concrete pools.