{"product_id":"seachem-reef-kalkwasser","title":"Seachem Reef Kalkwasser","description":"\u003cp\u003e\u003cstrong\u003eSeachem Reef Kalkwasser\u003c\/strong\u003e is pure calcium hydroxide for mixing limewater, the classic way to hold calcium and pH steady in a reef aquarium. Dosed through your top-off water, it replenishes the calcium your corals pull from the water while gently lifting pH, all without clouding the tank or spiking alkalinity. It is a budget-friendly cornerstone of our \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/additives-supplements\"\u003ereef additives and supplements\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#FFF8E1;border-left:4px solid #F9A825;padding:10px 14px;margin:0 0 14px;font-size:0.95em;\"\u003e\n\u003cstrong\u003eHandle with care.\u003c\/strong\u003e Kalkwasser is caustic calcium hydroxide. Wear gloves and eye protection, avoid breathing the dust, and never add the dry powder straight to your tank. Always dissolve it in fresh water first and drip the clear solution in slowly.\n\u003c\/div\u003e\n\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #006064;padding-left:8px;\"\u003eHow Kalkwasser Works\u003c\/h3\u003e\n\u003cp\u003eMixed into fresh RO or DI water, calcium hydroxide forms a saturated limewater solution. As that solution drips into your reef, it delivers calcium and hydroxide ions that combine with dissolved CO2 to raise pH and replenish the calcium and carbonate corals need to build their skeletons. Because it rides in on your evaporation top-off, it doses continuously and quietly, day and night.\u003c\/p\u003e\n\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #006064;padding-left:8px;\"\u003eWhy Reefkeepers Use It\u003c\/h3\u003e\n\u003cul style=\"margin:4px 0 12px;padding-left:20px;line-height:1.6;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaintains calcium\u003c\/strong\u003e at natural seawater levels for steady coral and coralline growth.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRaises and stabilizes pH\u003c\/strong\u003e without adding to carbonate alkalinity, ideal for CO2-heavy tanks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecipitates phosphate\u003c\/strong\u003e, helping keep nuisance algae in check as a side benefit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePennies per dose\u003c\/strong\u003e, a jar lasts a long time compared to two-part and liquid calcium.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomation friendly\u003c\/strong\u003e, pairs perfectly with a dosing pump or auto top-off reservoir.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3 style=\"margin:14px 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\u003eAdd 3 g (about 1 teaspoon) of Kalkwasser per 4 L (1 US gallon) of fresh RO or DI water and stir to dissolve; use up to 6 g per gallon for a fully saturated solution. Let it settle, then drip the clear limewater into a high-flow area of the sump or display through your top-off, ideally overnight. Start slowly and monitor pH, adjusting the drip rate to keep pH between 8.3 and 8.4. Never add the dry powder or unsettled slurry directly to the tank.\u003c\/p\u003e\n\n\u003ch3 style=\"margin:14px 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%;margin:6px 0 12px;font-size:0.95em;\"\u003e\n\u003cthead\u003e\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;\"\u003eMakes (approx.)\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\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003e250 g (8.8 oz)\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eUp to ~80 gal of kalkwasser\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eNano and small reef tanks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003e500 g (1.1 lb)\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eUp to ~165 gal of kalkwasser\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eLarger reefs and regular dosers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3 style=\"margin:14px 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%;margin:6px 0 12px;font-size:0.95em;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;width:40%;background:#E0F7FA;font-weight:600;\"\u003eBrand\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eSeachem\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eComposition\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003ePure calcium hydroxide (kalkwasser)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eWater Type\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eSaltwater and reef aquariums only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eSupports\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003eCalcium, pH, coral and coralline growth\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eMix Rate\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003e3 g per gallon (up to 6 g saturated)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eTarget pH\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003e8.3 to 8.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;background:#E0F7FA;font-weight:600;\"\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #B2EBF2;padding:6px 10px;\"\u003e250 g, 500 g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3 style=\"margin:14px 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 style=\"margin:4px 0 12px;padding-left:20px;line-height:1.6;\"\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-trace\"\u003eSeachem Reef Trace\u003c\/a\u003e replenishes the trace elements corals consume alongside calcium.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-strontium\"\u003eSeachem Reef Strontium\u003c\/a\u003e supports strontium levels for stony coral and coralline algae.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/seachem-reef-plus\"\u003eSeachem Reef Plus\u003c\/a\u003e is a broad vitamin and amino acid supplement for a thriving reef.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/salt-water\"\u003eBrowse our saltwater and reef care\u003c\/a\u003e for the rest of your dosing routine.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #006064;padding-left:8px;\"\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eDo I dose this straight into the tank?\u003c\/strong\u003e\u003cbr\u003eNo. Always dissolve it in fresh water and drip the clear limewater in through your top-off. Adding the powder directly can spike pH and harm livestock.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat water should I mix it with?\u003c\/strong\u003e\u003cbr\u003eUse fresh RO or DI water, not saltwater. The kalkwasser goes into your evaporation top-off reservoir, which is fresh.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is it different from two-part dosing?\u003c\/strong\u003e\u003cbr\u003eKalkwasser is far cheaper and also lifts pH, but it delivers calcium and alkalinity together at a fixed ratio. Heavy-demand reefs often run kalkwasser plus a supplement for fine tuning.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it reef safe?\u003c\/strong\u003e\u003cbr\u003eYes, when dosed correctly by the drip method. This product is for saltwater reef systems only, not freshwater.\u003c\/p\u003e","brand":"Seachem","offers":[{"title":"250g\/8.8oz","offer_id":48257182630107,"sku":"393","price":12.45,"currency_code":"USD","in_stock":true},{"title":"500g\/1.1lb","offer_id":48257182662875,"sku":"397","price":15.62,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/5209\/3403\/files\/0393-Reef-Kalkwasser-250-g.png?v=1770992542","url":"https:\/\/squeakysaquatics.com\/products\/seachem-reef-kalkwasser","provider":"Squeaky's Aquatics","version":"1.0","type":"link"}