{"product_id":"pond-filter-replacement-sponge-uk-biological-filter-media-fits-most-pond-filters-easy-clean","title":"Pond Filter Replacement Sponge UK | Biological Filter Media | Fits Most Pond Filters | Easy Clean","description":"\u003ch1\u003ePond Filter Replacement Sponge UK | Biological Filter Media | Fits Most Pond Filters\u003c\/h1\u003e\n\u003cp\u003e\u003cstrong\u003ePond filter replacement sponges provide essential biological and mechanical filtration, removing harmful ammonia, nitrites, and suspended particles from pond water. Compatible with most pressurised and box pond filters. Available in two sizes for ponds up to 5,000 and 12,000 litres. Easy to clean and long lasting.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch2\u003eWhy Your Pond Filter Sponge Matters\u003c\/h2\u003e\n\u003cp\u003eThe biological filter sponge is arguably the most critical component in your pond's ecosystem. Beneficial nitrifying bacteria colonise the open-cell foam structure, processing toxic ammonia into nitrites, then into nitrates. Without a healthy, well-maintained filter sponge, ammonia levels can spike rapidly — particularly in warmer months — causing fish stress, disease, and potentially fatal consequences.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e✅ Open-cell foam structure — maximises surface area for beneficial bacteria\u003c\/li\u003e\n\u003cli\u003e✅ Dual mechanical and biological filtration\u003c\/li\u003e\n\u003cli\u003e✅ Compatible with most pressurised pond filters and box filters\u003c\/li\u003e\n\u003cli\u003e✅ Can be trimmed to exact size with scissors\u003c\/li\u003e\n\u003cli\u003e✅ Reusable — rinse and reinstall, or replace when worn\u003c\/li\u003e\n\u003cli\u003e✅ Fish safe — no chemical treatment or additives\u003c\/li\u003e\n\u003cli\u003e✅ Two sizes: small (up to 5,000 L) and large (up to 12,000 L)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eSmall\u003c\/th\u003e\n\u003cth\u003eLarge\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable For\u003c\/td\u003e\n\u003ctd\u003eFilters for ponds up to 5,000 L\u003c\/td\u003e\n\u003ctd\u003eFilters for ponds up to 12,000 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFoam Type\u003c\/td\u003e\n\u003ctd\u003eOpen-cell polyurethane foam\u003c\/td\u003e\n\u003ctd\u003eOpen-cell polyurethane foam\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColour\u003c\/td\u003e\n\u003ctd\u003eBlack or Dark Grey\u003c\/td\u003e\n\u003ctd\u003eBlack or Dark Grey\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCan Be Trimmed?\u003c\/td\u003e\n\u003ctd\u003eYes — scissors or knife\u003c\/td\u003e\n\u003ctd\u003eYes — scissors or knife\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFish Safe\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDelivery\u003c\/td\u003e\n\u003ctd colspan=\"2\"\u003eFree UK delivery\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eHow to Clean Your Filter Sponge (Without Killing Bacteria)\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eNever rinse filter sponges under tap water.\u003c\/strong\u003e Chlorine and chloramine kill the beneficial bacteria living in the sponge, effectively resetting your filter's biological cycle and causing a dangerous ammonia spike. Instead, squeeze the sponge in a bucket of water taken directly from the pond until the water runs relatively clear. Reinstall immediately.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cstrong\u003eHow do I know when to replace rather than clean the sponge?\u003c\/strong\u003e\u003c\/dt\u003e\n\u003cdd\u003eIf the foam has visibly deteriorated — crumbling, tearing, or permanently compacted despite cleaning — it's time to replace it. A healthy sponge springs back to its original shape when squeezed. Most last 2–4 years with regular cleaning.\u003c\/dd\u003e\n\u003cdt\u003e\u003cstrong\u003eWill it fit my filter?\u003c\/strong\u003e\u003c\/dt\u003e\n\u003cdd\u003eThe sponges can be trimmed with scissors or a sharp knife to fit virtually any filter chamber. Measure your filter's chamber before ordering.\u003c\/dd\u003e\n\u003cdt\u003e\u003cstrong\u003eCan I use it in a box gravity-fed filter?\u003c\/strong\u003e\u003c\/dt\u003e\n\u003cdd\u003eYes. The sponge is suitable for both pressurised filters and open-top box gravity-fed filters. Cut to fit as required.\u003c\/dd\u003e\n\u003cdt\u003e\u003cstrong\u003eShould I cycle a new sponge before using it?\u003c\/strong\u003e\u003c\/dt\u003e\n\u003cdd\u003eA new sponge takes 4–6 weeks to fully colonise with beneficial bacteria. Adding a liquid biological filter starter when installing speeds this process significantly.\u003c\/dd\u003e\n\u003cdt\u003e\u003cstrong\u003eShould I replace all sponges at once?\u003c\/strong\u003e\u003c\/dt\u003e\n\u003cdd\u003eNo — replace sponges one at a time to preserve as much of the existing bacterial colony as possible.\u003c\/dd\u003e\n\u003c\/dl\u003e\n\u003cp\u003e🚚 \u003cstrong\u003eFree UK Delivery\u003c\/strong\u003e | 🐟 \u003cstrong\u003eFish Safe\u003c\/strong\u003e | ✅ \u003cstrong\u003eUK Pond Expert Approved\u003c\/strong\u003e\u003c\/p\u003e","brand":"PondLiners Co","offers":[{"title":"Small up to 5000L","offer_id":57667097002332,"sku":"PLF-FM001-S","price":54.0,"currency_code":"GBP","in_stock":true},{"title":"Large up to 12000L","offer_id":57667097035100,"sku":"PLF-FM001-L","price":84.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0889\/2035\/9260\/files\/321838c85272af5db7042b37a42c1e97.jpg?v=1779043412","url":"https:\/\/www.pondlinersco.co.uk\/products\/pond-filter-replacement-sponge-uk-biological-filter-media-fits-most-pond-filters-easy-clean","provider":"PondLinersco.co.uk","version":"1.0","type":"link"}