{"product_id":"seachem-reef-builder","title":"Seachem Reef Builder","description":"\u003cp\u003e\u003cstrong\u003eSeachem Reef Builder\u003c\/strong\u003e is a dry blend of carbonate salts that raises carbonate alkalinity (KH) in a reef aquarium without immediately changing pH. Alkalinity is what keeps your pH stable and gives stony corals and coralline algae the carbonate they need to build skeleton, so when it drifts low your whole tank gets harder to keep steady. Reef Builder restores it cleanly, and with long term use it gently tends to stabilize pH around 8.3. Browse our full range of \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/additives-supplements\"\u003ereef additives and supplements\u003c\/a\u003e and the rest of the \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/seachem\"\u003eSeachem lineup\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eWhy Reefers Use It\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRaises KH, not pH.\u003c\/strong\u003e Restores carbonate alkalinity without the pH spike, so you can correct alkalinity even when your pH is already where you want it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProtects the rest of your chemistry.\u003c\/strong\u003e Used as directed it will not deplete calcium, magnesium, or strontium, which often precipitate out when alkalinity is pushed up carelessly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStabilizes over time.\u003c\/strong\u003e With ongoing use pH tends to settle and hold near the natural reef target of 8.3.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePairs with Reef Buffer.\u003c\/strong\u003e Use the two together to dial in both alkalinity and pH independently.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eHow to Use\u003c\/h3\u003e\n\u003cp\u003eDissolve 3 g (about 1\/2 level teaspoon) in at least 250 mL of fresh water, then add it to the tank for every 150 L (40 US gallons), twice a week or as needed to hold your numbers in range. Each 3 g per 150 L raises alkalinity by roughly 0.25 meq\/L (about 0.7 dKH). Do not exceed 12 g per 150 L in a single day. Keep reef alkalinity in the 3 to 5 meq\/L (8 to 14 dKH) range and never let it fall below 2 meq\/L.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e do not directly mix Reef Builder with any calcium, magnesium, or strontium supplement. Add your alkalinity and calcium products on alternate days, or at least 30 minutes apart, so they do not react in the water column.\u003c\/p\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eReef Builder or Reef Buffer?\u003c\/h3\u003e\n\u003cp\u003eThey sound alike but do different jobs. \u003cstrong\u003eReef Builder\u003c\/strong\u003e raises carbonate alkalinity without affecting pH. \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-buffer-ph-alkalinity-83\"\u003eReef Buffer\u003c\/a\u003e raises carbonate alkalinity and pH together, toward 8.3. Reach for Reef Builder when your pH is already on target and you just need to bring KH up. Reach for Reef Buffer when your pH is running low. The two can be used in the same system.\u003c\/p\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eChoose Your Size\u003c\/h3\u003e\n\u003ctable style=\"border-collapse: collapse; width: 100%; font-size: 0.95em;\"\u003e\n\u003cthead\u003e\n\u003ctr style=\"background: #E0F7FA;\"\u003e\n\u003cth style=\"border: 1px solid #B2EBF2; padding: 6px 10px; text-align: left;\"\u003eSize\u003c\/th\u003e\n\u003cth style=\"border: 1px solid #B2EBF2; padding: 6px 10px; text-align: left;\"\u003eApprox. Doses\u003c\/th\u003e\n\u003cth style=\"border: 1px solid #B2EBF2; padding: 6px 10px; text-align: left;\"\u003eBest For\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003e50 g\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e~16\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eNano and pico reefs, or trying it out\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003e300 g\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e~100\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eSmall to medium reefs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003e600 g\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e~200\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eEstablished medium reefs on a regular schedule\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003e1.2 kg\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e~400\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eLarge or SPS-heavy reefs, best value per dose\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp style=\"font-size: 0.9em; color: #555; margin: 6px 0 0;\"\u003eEach dose is 3 g treating 150 L (40 US gallons). Actual usage depends on your tank's alkalinity demand.\u003c\/p\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"border-collapse: collapse; width: 100%; font-size: 0.95em;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px; width: 38%;\"\u003e\u003cstrong\u003eType\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eDry carbonate alkalinity (KH) supplement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eWater type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eMarine and reef only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eDose\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e3 g (1\/2 tsp) per 150 L (40 gal), twice weekly\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eRaises alkalinity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e~0.25 meq\/L (~0.7 dKH) per 3 g \/ 150 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eTarget range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e3 to 5 meq\/L (8 to 14 dKH)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eEffect on pH\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003eNone immediately; stabilizes near 8.3 over time\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e\u003cstrong\u003eSizes\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #B2EBF2; padding: 6px 10px;\"\u003e50 g, 300 g, 600 g, 1.2 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eRecommended Pairings\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-advantage-calcium-supplement\"\u003eSeachem Reef Advantage Calcium\u003c\/a\u003e for the calcium side of the balance.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-advantage-magnesium\"\u003eSeachem Reef Advantage Magnesium\u003c\/a\u003e to keep calcium and alkalinity holding where you set them.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-buffer-ph-alkalinity-83\"\u003eSeachem Reef Buffer\u003c\/a\u003e when you need to raise pH along with alkalinity.\u003c\/li\u003e\n\u003cli\u003eA reliable \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/water-testing\"\u003ealkalinity test kit\u003c\/a\u003e so you are always dosing to a real number.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin: 16px 0 4px; font-size: 1.05em; font-weight: 600; line-height: 1.25; border-left: 4px solid #006064; padding-left: 8px;\"\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does Reef Builder actually do?\u003c\/strong\u003e\u003cbr\u003eIt raises carbonate alkalinity (KH) in a marine tank without immediately changing pH, giving corals and coralline algae the carbonate they need while keeping pH steady.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it raise my pH?\u003c\/strong\u003e\u003cbr\u003eNot right away. Reef Builder is designed to lift alkalinity on its own, and with continued use pH tends to settle near 8.3. If you specifically need to bring pH up, use Reef Buffer instead or alongside it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I dose it at the same time as my calcium supplement?\u003c\/strong\u003e\u003cbr\u003eNo. Do not directly mix it with calcium, magnesium, or strontium products. Dose them on alternate days, or at least 30 minutes apart.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much will one dose move my alkalinity?\u003c\/strong\u003e\u003cbr\u003eRoughly 0.25 meq\/L (about 0.7 dKH) per 3 g in 150 L (40 gallons). Always test and adjust toward the 3 to 5 meq\/L target.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it in freshwater?\u003c\/strong\u003e\u003cbr\u003eNo. Reef Builder is formulated for marine and reef aquariums only.\u003c\/p\u003e","brand":"Seachem","offers":[{"title":"50 g","offer_id":48755757318363,"sku":"364","price":3.87,"currency_code":"USD","in_stock":true},{"title":"300 g","offer_id":48755757351131,"sku":"366","price":7.47,"currency_code":"USD","in_stock":true},{"title":"600 g","offer_id":48755757383899,"sku":"363","price":12.75,"currency_code":"USD","in_stock":true},{"title":"1.2 kg","offer_id":48755757416667,"sku":"367","price":23.16,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/5209\/3403\/files\/0364-Reef-Builder-50-g.png?v=1778225528","url":"https:\/\/squeakysaquatics.com\/products\/seachem-reef-builder","provider":"Squeaky's Aquatics","version":"1.0","type":"link"}