Pentair · Pentair Pool Products
FNS Plus
Diatomaceous-earth (DE) pool filter · sub-micron filtration · in service at New Hope
The Pentair FNS Plus DE filter tank on the pool equipment pad — large near-vertical fibreglass tank, weathered white, with PVC plumbing branching off the top and pressure gauge mounted on the multiport valve to the left. Captured 26 May 2026. Close-up of the yellow FNS Plus identity label on the filter tank — Pentair Pool Products branding, FNS Plus wordmark, the multi-language safety pictograms (do-not-stand, do-not-overpressurize). The label is the canonical model identifier. The filter pressure gauge — round black-bezel dial with red CLEAN FILTER warning band and a START arrow. Current reading captured in the photo serves as the baseline pressure to compare against on subsequent inspections; backwash trigger is typically clean+10 psi.
Model
Pentair FNS Plus DE Filter · "FNS" = Fibre-Reinforced Filter, Side-mounted DE · sub-micron-grade filtration via DE-coated grid plates · standard residential models FNSP24 / FNSP36 / FNSP48 / FNSP60 (sq.ft. of grid area)
Tank size / model variant
TBD — confirm sq.ft. of grid area from the side-of-tank model placard or the original installer paperwork · grid area drives flow rating and DE-charge recipe
Position in the loop
Downstream of IntelliFlo VS-F pump · upstream of Hayward HeatPro heat pump · DE-grid plates polish incoming water before it reaches the heater; back-pressure rises as DE bed loads up
Clean baseline pressure
TBD — capture a fresh reading right after the next backwash and DE-recharge · that becomes the reference point for the +10 psi backwash trigger
Backwash trigger
Clean baseline + 10 psi · Pentair's published rule of thumb · once you backwash, recharge DE per spec (typically ~1 lb DE per 5 sq.ft. of grid area)
DE charge recipe
TBD — depends on confirmed sq.ft. above; capture DE bag SKU + lbs-per-recharge on first service entry
Location
pa · 6279 Greenhill Road, New Hope PA 18938 · pool equipment pad, between the IntelliFlo VS-F and the HeatPro heat pump
Expected operational life
Tank + manifold typically 15–20 years; DE grid plates 5–10 years before fabric pinholes start letting DE through to the return jets. Replacement program is grid-set first (~$200-400), tank rarely.
Current status
Photographed and inventoried 26 May 2026. Tank exterior shows weathered finish but no cracks visible. Next steward actions: (1) capture sq.ft. grid area from tank placard, (2) baseline clean-pressure reading after next backwash, (3) DE-recharge recipe locked in record.
Manufacturer resources

Service log

No entries yet. First entry priorities: (1) record sq.ft. grid area, (2) baseline clean psi, (3) initial inspection of grid plates for pinholes, (4) DE-charge weight.

Cross-references