PRO Series® Filter Cleaner™ 20321 1 gal. Pro Series Filter Cleaner is a highly concentrated deep cleaning solution that removes buildup caused by: oils, grease, non-living organics and more on filters. It is very effective on cartridge elements, D.E. filter grids, sand filters and regenerative media filters. Pro Series Filter Cleaner improves filter efficiency and lengthens cycles between filter cleaning. Pro Series Filter Cleaner is compatible with chlorine, bromine and alternative sanitizing systems.