SQ 4.9sqft HRPB Series Sand Filter How to filter your pool filter in 60 seconds or less And, that includes the walk from your easy chair to the HRPB Filters. Simply apply a little two-way wrist action on the control valve and the filter is hard at work cleaning itself. Through innovative engineering, the filter's dirt-handling capacity is maximized, which extends the time between cleanings (backwashing). Features Typical Installation Inground pools, inground hot tubs, industrial applications (including cooling towers), and water features (including fish ponds and water gardens)