{"product_id":"tier1-pool-filter-cartridge-replacement-for-pentair-rainbow-25-2-pack-nsf-50-tested-trilobal-media","title":"Tier1 Pool Filter Cartridge Replacement for Pentair Rainbow 25 — 2-Pack, NSF-50 Tested Trilobal Media","description":"\u003cp\u003e\u003cstrong\u003eTier1 Replacement Pentair Rainbow 25 Pool Filter (2-Pack) are direct-fit, NSF-50 tested filter cartridges engineered to restore clear pool water by trapping fine debris while maintaining steady flow.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThese Tier1 cartridges replace a wide range of legacy filter elements (including Dynamic 17-2327, Pleatco PRB25-IN, Unicel C-4326 and Filbur FC-2375) and are built to the same outer dimensions so they slide into compatible systems without modification. The pair includes a high-flow internal core and trilobal dirt-lock media designed to capture more particles than traditional round fibers. They are intended for pool owners and service technicians who want a reliable, affordable alternative to OEM cartridges.\u003c\/p\u003e\n\n\u003ch3\u003eHow do these cartridges fit my existing Pentair Rainbow 25 system?\u003c\/h3\u003e\n\u003cp\u003eThese cartridges are sized to match the Rainbow 25 and equivalent models so installation is plug-and-play with compatible housings. No trimming or adapters are usually required.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eExact cartridge dimensions: 13-5\/16\" x 4-15\/16\" for correct seating.\u003c\/li\u003e\n  \u003cli\u003eCompatible with many cross-reference part numbers for easy replacement.\u003c\/li\u003e\n  \u003cli\u003eDesigned to form a secure seal to minimize bypass and leakage.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat performance improvements can I expect over standard cartridges?\u003c\/h3\u003e\n\u003cp\u003eThe trilobal fiber construction increases surface area and mechanical capture, so the cartridges trap more dirt, hair and fine particles while supporting good water throughput. The internal core maintains steady flow without creating excessive pressure on the pump.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eTrilobal dirt-lock media captures up to 40% more debris than round fibers.\u003c\/li\u003e\n  \u003cli\u003eHigh-flow internal core supports consistent circulation and pump protection.\u003c\/li\u003e\n  \u003cli\u003eMedia design balances fine filtration with service life and flow efficiency.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eAre these cartridges durable and safe for pool systems?\u003c\/h3\u003e\n\u003cp\u003eTier1 cartridges are tested to NSF 50 performance protocols for pool filtration, providing an independent measure of durability and function. They are constructed to withstand normal pool environments and repeated cleanings when maintained properly.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIndependently tested to NSF 50 standards for filtration performance.\u003c\/li\u003e\n  \u003cli\u003eRobust pleat structure resists collapse during operation and cleaning.\u003c\/li\u003e\n  \u003cli\u003eBuilt to hold shape across multiple service cycles when rinsed correctly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow should I maintain these filter cartridges for longest life?\u003c\/h3\u003e\n\u003cp\u003eRoutine rinsing with a hose and occasional deep cleaning will keep pleats working efficiently. Replace cartridges when damage, permanent staining, or flow decline indicates lost effectiveness.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRinse pleats weekly during heavy use seasons to remove trapped debris.\u003c\/li\u003e\n  \u003cli\u003eUse cartridge cleaner periodically for oil or mineral buildup; follow cleaner directions.\u003c\/li\u003e\n  \u003cli\u003eReplace both cartridges in the set when pleats tear, core deforms, or pressure rises noticeably.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for? Pool owners, property managers, and service technicians who need a cost-effective replacement for Pentair Rainbow 25 and cross-referenced cartridges will find this Tier1 2-pack appropriate. It’s aimed at users who want improved particle capture with maintained pump flow, NSF-50 tested assurance, and a straightforward, direct-fit swap for older or matching filtration systems.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Will these fit my Pentair Rainbow 25 filter?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes—this Tier1 cartridge matches Rainbow 25 dimensions and cross-reference part numbers for a direct fit in compatible housings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: How often should I replace the cartridges?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Replace when pleats are damaged, flow drops significantly, or after repeated deep cleanings; many pools need replacement every 1–2 seasons depending on use.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Tier1","offers":[{"title":"Default Title","offer_id":56830052172116,"sku":"B07D94HH2L","price":85.46,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1063\/2652\/4244\/files\/tier1-front-packaging-view.jpg?v=1787000651","url":"https:\/\/gardenluxe.co.uk\/products\/tier1-pool-filter-cartridge-replacement-for-pentair-rainbow-25-2-pack-nsf-50-tested-trilobal-media","provider":"Gardenluxe Uk","version":"1.0","type":"link"}