Arctic Spas spa filters

Arctic Spas does not have its own table in the Unicel guide; it points owners to the Blue Falls Mfg. Ltd. (Canada) listing, and Filbur lists the same cartridges under both Arctic Spas and Blue Falls. The two cartridges named are the 4-15/16" × 13-5/16" C-4326 (25 sq ft) and C-4950 (50 sq ft). Arctic dealers sell the 50 sq ft drop-in as factory part PRT-115LOT for spas built in 2008 or earlier.

From 2009 Arctic spas use a threaded intake that these open-ended cartridges do not fit, and 2020-and-newer Custom Series spas use the Polar Pro system. The year-by-year split is on the Arctic Spas filter-by-year page. These rows duplicate cartridges covered under other brands, so they are kept out of search results.

This page lists 2 Arctic Spas replacement cartridges from the Unicel 2026 Replacement Guide, the Pleatco 2023 catalog, the Filbur catalog and manufacturer and retailer pages, plus model and model-year fitment for 1 of them (1 hot tub models in total). 2 have a Filbur number. Find your spa filter by the OEM part number on the end cap, or measure it and compare sizes below.

Clean and replace intervals for one cartridge on this list, plus the cross-reference numbers and a buy link: filter replacement schedule and reorder.

CartridgeUnicelPleatcoFilburSizeFitsStatus
C-4326 (Arctic Spas (Unicel lists Arctic under Blue Falls Mfg. Ltd., Canada))C-4326PRB25-INFC-23754-15/16" (125 mm) × 13-5/16" (338 mm), 25 sq ftnot listedverified
PRT-115LOTC-4950PRB50-INFC-23904-15/16" (125 mm) × 13-5/16" (338 mm), 50 sq ft1 modelverified

Know your model but not the part number? See Arctic Spas filter by model and year.

2 of these rows do not have enough detail for a stand-alone page (for example, no OEM number or no second cross-reference), so their pages are kept out of search results and this table is the main reference for them.

Brands that share cartridges with Arctic Spas

Guides that apply to Arctic Spas

Search Arctic Spas part numbers on Amazon

Each button opens an Amazon search for that part number. The cartridge page is where the cited size and fittings are. Match those before you buy.

Part numbers from this table

Disclosure: we may earn a commission from qualifying purchases made through retailer links on this site, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Amazon links on this page go to Amazon.com and are affiliate links; they never change what we write, and the list is not ranked by commission. Each “Search on Amazon” button opens an Amazon search for the part or product name shown, not a single listing we pre-checked. Check size, quantity and your spa maker’s guidance before you buy. See our affiliate disclosure.

Model-year fitment comes only from the sources named on each cartridge page. Where no source lists models or years, the page says so.