BioGuard Kleen It Filter Cleaner removes scale/clarifier deposits, dirt, and debris from the pool’s filter. This product is comprised of a dual-action formula that can prolong the life of your filter. It helps prevent scale build-up and rust. The experts recommend that this product should be used at least once per season to keep the filter clean. Kleen It has been proven not to damage the filter equipment and to be safe for all filter types.