{"product_id":"unicelreplacementfiltercartridge275sfmartecc4301unfc4301","title":"Unicel Replacement Filter Cartridge 27.5 sf Martec | C-4301","description":"\u003cdiv class=\"product-description\"\u003e\n  \u003ch2\u003eUnicel C-4301 Replacement Spa Filter Cartridge – 27.5 Sq Ft (Open Top \u0026amp; Bottom, 2-1\/8\" ID)\u003c\/h2\u003e\n\n  \u003cp\u003e\n    The Unicel C-4301 is a premium pleated replacement \u003cstrong\u003espa filter cartridge\u003c\/strong\u003e designed for select Martec and Sonfarrel-style\n    filter canisters that use a compact cartridge with \u003cstrong\u003eopen ends\u003c\/strong\u003e. It captures fine debris to help keep water clear while\n    maintaining strong circulation when rinsed and cleaned on a regular schedule.\n  \u003c\/p\u003e\n\n  \u003ch3\u003eKey Features\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003e27.5 sq ft\u003c\/strong\u003e filtration area for effective debris capture and steady spa flow\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOpen top \u0026amp; open bottom\u003c\/strong\u003e end caps for compatible standpipe-style housings\u003c\/li\u003e\n    \u003cli\u003eDurable pleated media and rigid inner core built for repeated cleaning cycles\u003c\/li\u003e\n    \u003cli\u003eDirect replacement when matched by part number and measurements\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eSpecifications\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e C-4301\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFiltration Area:\u003c\/strong\u003e 27.5 sq ft\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOutside Diameter:\u003c\/strong\u003e 4-15\/16\" (4.9375\")\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLength:\u003c\/strong\u003e 14-7\/8\" (14.875\")\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTop End Cap:\u003c\/strong\u003e Open\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTop Inside Diameter:\u003c\/strong\u003e 2-1\/8\" (2.125\")\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBottom End Cap:\u003c\/strong\u003e Open\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBottom Inside Diameter:\u003c\/strong\u003e 2-1\/8\" (2.125\")\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePleat Count (typical):\u003c\/strong\u003e 106\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFilter Media:\u003c\/strong\u003e 3 oz pleated media\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eReplaces \/ Cross References\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePleatco:\u003c\/strong\u003e PMT27.5\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFilbur:\u003c\/strong\u003e FC-1610 (some catalogs also reference FC-1616)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCommon OEM \/ System References:\u003c\/strong\u003e Martec \/ Sonfarrel 25-220122 (verify by measurements)\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eWhen to Replace\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003ePleats are torn, frayed, or separating from end caps\u003c\/li\u003e\n    \u003cli\u003eFilter stays restrictive even after a thorough rinse and deep clean\u003c\/li\u003e\n    \u003cli\u003eWater stays cloudy despite balanced chemistry and proper sanitizer levels\u003c\/li\u003e\n    \u003cli\u003eEnd caps are cracked\/warped or the inner core is weakening\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eRelated Products\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=Unicel%20C-4301\"\u003eUnicel C-4301 (Shop \/ Options)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=Pleatco%20PMT27.5\"\u003ePleatco PMT27.5 (Alternate)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=Filbur%20FC-1610\"\u003eFilbur FC-1610 (Alternate)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=spa%20cartridge%20filter%20cleaner\"\u003eSpa Cartridge Filter Cleaner\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=cartridge%20cleaning%20wand\"\u003eCartridge Cleaning Wand\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/search?q=spa%20water%20test%20strips\"\u003eSpa Water Test Strips\u003c\/a\u003e\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eMaintenance Tips\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eRinse the cartridge regularly (often weekly with heavy spa use) to prevent restriction and keep jets performing well.\u003c\/li\u003e\n    \u003cli\u003eDeep clean every 3–6 weeks with a cartridge cleaner to remove oils; rinse thoroughly before reinstalling.\u003c\/li\u003e\n    \u003cli\u003eIf scale is present, degrease first, then treat for scale, and rinse completely before returning to service.\u003c\/li\u003e\n    \u003cli\u003eRotating between two cartridges (one in use, one drying after cleaning) can extend overall filter life and improve performance.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n","brand":"Unicel","offers":[{"title":"Default Title","offer_id":52589962658108,"sku":"C-4301","price":32.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0736\/3280\/9276\/files\/unicel-replacement-filter-cartridge-275-sf-martec-c-4301-cartridges-3983900.jpg?v=1770393385","url":"https:\/\/aquapoolsupply.com\/products\/unicelreplacementfiltercartridge275sfmartecc4301unfc4301","provider":"Aqua Pool Supply","version":"1.0","type":"link"}