Pentair Clean & Clear/Posi-Clear Tank O-ring

The Pentair Clean & Clear/Posi-Clear Tank O-Ring (part number 39006000) is a critical sealing gasket engineered specifically for Pentair Clean & Clear, Clean & Clear Predator, Posi-Clear, and Posi-Clear RP single-cartridge pool and spa filtration systems. Molded from a premium, heavy-duty synthetic rubber compound, this large-diameter circular O-ring sits precisely inside the perimeter groove between the upper filter lid and the lower tank bottom. Its primary structural function is to create an absolute airtight and watertight compression seal when the locking ring is tightened, allowing the filter shell to safely contain high internal hydraulic pressures without leaking. Designed to retain its elasticity and resist degradation despite continuous exposure to chlorine, bromine, UV rays, and fluctuating water temperatures, this O-ring is essential for maintaining proper system pressure. Due to its large circumference and robust cross-sectional thickness, this durable rubber component has a product and shipping weight of approximately 0.31 pounds (about 5 ounces), making it a substantial yet easily manageable replacement part for routine filter maintenance.