Pentair Tank Bottom Assembly

The term Pentair Tank Bottom Assembly generically describes the structural lower pressure vessel base used across Pentair’s flagship pool and spa filter lines—most notably the FNS Plus D.E. Series (Parts #170015 through #170018) and the Clean & Clear Plus / Quad D.E. Series (Part #178578). Injection-molded from a dense, fiberglass-reinforced polypropylene polymer, this thick-walled basin anchors the entire system. It is engineered to absorb continuous hydraulic stresses, chemical pool environments, and heavy UV exposure without cracking. It features pre-molded baseline openings that receive the internal collection manifolds, lower bulkhead union fittings, and a threaded winterizing drain port. By providing an independent lower housing replacement, it allows pool technicians to repair fractured filter bases without the enormous expense of buying an entirely new filtration system.

Because the physical size of this vessel scales dramatically based on the filter's square footage capacity, its weight varies by model:

• Small Cartridge/D.E. Base (e.g., Posi-Clear PXC or FNS Plus 24): Actual product weight is approximately 12.0 pounds.

• Medium/Large Base (e.g., FNS Plus 36/48 or Clean & Clear Plus): Actual product weight ranges from 25.0 to 30.0 pounds.

• Commercial Extra-Large Base (e.g., FNS Plus 60 with complete internal plumbing): Shipping and boxed transit weights can scale from 33.0 up to 131.0 pounds due to the heavy internal standpipes, massive crate dimensions, or freight-freighted packaging demands.