Unicel C-8399 Replacement Filter for Caldera Spas 72831

Overview

The Unicel C-8399 is a pleated polyester spa cartridge filter element engineered for Caldera Spas circulation systems, providing 100 sq ft of filtration area in a single-element configuration. Dimensional specifications: 8.0-inch OD, 4.0-inch ID at the open top end, with an overall length of 9.75 inches. Media construction utilizes Reemay nonwoven spunbond polyester at a nominal 20-micron filtration efficiency, supported on a perforated PVC core for axial rigidity under spa pump operating pressures. End cap configuration features a closed-bottom, open-top molded ABS design with a 4-inch SAE-style top opening for direct manifold seating. Maximum continuous service temperature is rated at 115°F with intermittent excursion capability to 120°F, suitable for the elevated thermal duty cycle characteristic of high-use spa applications. Operating pressure range: 5–25 PSI.

Service interval recommendation: rinse with fresh water every 2–4 weeks to remove gross particulate loading; perform chemical soak with dilute TSP or commercial enzyme cleaner every 4–6 weeks to displace accumulated body oils, surfactants, and cosmetic residues that resist rinse-only maintenance. Replacement is recommended at 12–15 month intervals under typical residential spa use, or at ΔP ≥ 5 PSI above clean operating baseline, whichever occurs first. Chemical compatibility: polyester media and ABS end caps tolerate continuous service at ≤ 10 ppm free available chlorine or ≤ 30 ppm total bromine; muriatic acid wash at 1:20 dilution is compatible for calcium scale removal (20-minute maximum exposure, thorough fresh water rinse required prior to reinstallation). Enzyme cleaners are compatible without restriction. Standard Unicel 90-day manufacturing defect warranty applies through authorized distribution.

What's Included

Your order includes the selected quantity of replacement spa filter cartridges. Each unit is individually inspected for quality before shipping.