JBL AlgoPond Sorb: Natural colour extracts found in peat produce a light amber discolouration of the water, acting like sunglasses to eliminate a specific spectral range of light. This blocks some of the light rays vital for algae to grow, slowing down growth. The pH level and carbonate hardness remain unchanged.JBL AlgoPond Sorb -bio-algae blocker for the pond+ reduces algae growing using sunglasses effect+ blocks some of the light rays vital for algae to grow+ effectiveness indicated by light amber discolouring of water+ does not reduce pH or hardness levelsDosage JBL AlgoPond Sorb40 ml per 700-800 l pond water. Every 4 weeks from early spring: In a watering can, mix the required amount with pond water and carefully spread over the pond. Do not filter through active carbon.