Blue Horizons JellyClear Cubes are clarification gel blocks offered in single use JellyClear Cube presentation pack. The JellyClear Cube improve filtration efficiency by coagulating debris and "tightening" the filter bed. Easy and safe to use in skimmers or weirs, each gel block treats up to 50,000 litres (11,000 gallons) for up to 2 weeks. Please refer to the Blue Horizons Pool Care guide for further product information in our downloads section. JellyClear Cubes Application Instructions: Ensure algae is pre-treated (previous 24 hours) to release algae from walls, prior to using JellyClear Cubes. Adjust pH to desired range of 7.2 - 7.6. Backwash the filter (or clean the cartridge) and then return to the normal filtration setting prior to use. Peel off the protective plastic film and insert the JellyClear Cubes direclty into the pump strainer basket OR the skimmer/weir basket. JellyClear Cubes will dissolve over a period of 3 - 4 days depending on water flow from the filtrat