{"product_id":"red-sea-marine-care-magnesium-test-kit","title":"Red Sea Marine Care Magnesium Test Kit","description":"\u003cp\u003e\u003cstrong\u003eThe element that keeps calcium and alkalinity honest.\u003c\/strong\u003e The Red Sea Marine Care Magnesium Test Kit measures magnesium in marine and reef aquariums by titration — a precise syringe drop-count read straight off the syringe barrel. Magnesium sits quietly in the background of every calcium and alkalinity swing; when either won't hold steady, magnesium is usually the reason.\u003c\/p\u003e\u003ch3\u003eKey features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e75 titration tests per kit\u003c\/strong\u003e — magnesium moves slowly, so this typically lasts well over a year of monthly testing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSelectable resolution\u003c\/strong\u003e — 100 ppm for a fast check, 50 ppm when you need to confirm a dosing change landed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTitration method\u003c\/strong\u003e — dose reagent by the drop with the supplied 5 mL syringe until the colour changes; the drop count is the reading.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConversion chart included\u003c\/strong\u003e — reads the drop count straight to ppm.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMeasures\u003c\/td\u003e\n\u003ctd\u003eMagnesium (Mg)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMethod\u003c\/td\u003e\n\u003ctd\u003eTitration (syringe drop-count)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResolution\u003c\/td\u003e\n\u003ctd\u003eSelectable 50 ppm or 100 ppm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTests per kit\u003c\/td\u003e\n\u003ctd\u003e75\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWater type\u003c\/td\u003e\n\u003ctd\u003eMarine and reef\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStorage\u003c\/td\u003e\n\u003ctd\u003eSealed, 15–25°C, use before the expiry date printed on the pack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eWhat's included \/ Not included\u003c\/h3\u003e\u003cp\u003eThe kit includes Reagent A (15 mL), Reagent B (15 mL), Reagent C (50 mL), a 5 mL syringe, a glass test vial and printed instructions with a colour reference card — everything needed for 75 tests. It does not include a calcium or alkalinity test; those are separate kits, best run alongside this one rather than in isolation.\u003c\/p\u003e\u003ch3\u003eSuitable for, and not suitable for\u003c\/h3\u003e\u003cp\u003eSuitable for any marine or reef system, and most useful in mixed reef and SPS tanks where calcium and alkalinity are being dosed regularly. Less critical on a fish-only tank with no calcifying livestock, where magnesium rarely drifts.\u003c\/p\u003e\u003ch3\u003eTarget ranges\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSystem type\u003c\/th\u003e\n\u003cth\u003eTarget magnesium\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFOWLR (fish only with live rock)\u003c\/td\u003e\n\u003ctd\u003e1,250–1,350 mg\/L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMixed reef \/ soft and LPS coral\u003c\/td\u003e\n\u003ctd\u003e1,300–1,400 mg\/L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSPS-dominated reef\u003c\/td\u003e\n\u003ctd\u003e1,300–1,400 mg\/L, held alongside calcium 420–450 mg\/L and alkalinity 7–9 dKH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003eThese are marine and reef target ranges. Magnesium is not a parameter tracked in freshwater community, planted or African cichlid tanks, so no freshwater target range applies to this kit.\u003c\/p\u003e\u003ch3\u003eWhat to do when the reading is out of range\u003c\/h3\u003e\u003cp\u003eLow magnesium is corrected with a magnesium supplement such as \u003ca href=\"\/products\/red-sea-reef-care-magnesium-foundation-c\"\u003eRed Sea Reef Care Magnesium Foundation C\u003c\/a\u003e. Raise it gradually rather than in one large dose, and retest a few days later rather than immediately — magnesium takes time to fully equilibrate through the water column.\u003c\/p\u003e\u003ch3\u003eCare and storage\u003c\/h3\u003e\u003cp\u003eKeep sealed, store between 15–25°C out of direct sun, and check the expiry date printed on the pack before trusting an older kit's result.\u003c\/p\u003e\u003ch3\u003eWarranty and delivery\u003c\/h3\u003e\u003cp\u003eCovered by the consumer guarantees under Australian Consumer Law, in addition to any manufacturer undertaking. Standard parcel freight — no special handling required.\u003c\/p\u003e\u003ch3\u003eGoes well with\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/red-sea-marine-care-calcium-test-kit\"\u003eRed Sea Marine Care Calcium Test Kit\u003c\/a\u003e — test together; magnesium stabilises calcium.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/red-sea-kh-alkalinity-pro-testing-kit-75-tests\"\u003eRed Sea KH\/Alkalinity Pro Testing Kit\u003c\/a\u003e — the third leg of the calcium\/alkalinity\/magnesium triangle.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/red-sea-reef-care-magnesium-foundation-c\"\u003eRed Sea Reef Care Magnesium Foundation C\u003c\/a\u003e — the matching dosing solution when magnesium reads low.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eCommon questions\u003c\/h3\u003e\u003ch4\u003eWhy does low magnesium affect calcium and alkalinity?\u003c\/h4\u003e\u003cp\u003eMagnesium keeps calcium and carbonate in solution at reef-tank concentrations. When magnesium is low, calcium and alkalinity become harder to raise and hold — dosing either one just gets consumed faster or precipitates out.\u003c\/p\u003e\u003ch4\u003eHow often should I test magnesium?\u003c\/h4\u003e\u003cp\u003eMonthly is enough for most tanks — it moves far more slowly than calcium or alkalinity.\u003c\/p\u003e\u003ch4\u003eMy calcium and alkalinity won't hold steady even though I'm dosing correctly — what should I check?\u003c\/h4\u003e\u003cp\u003eTest magnesium. A low reading is the most common hidden cause of calcium and alkalinity instability in an otherwise well-dosed tank.\u003c\/p\u003e\u003ch4\u003eIs this the same as the Magnesium Pro test kit?\u003c\/h4\u003e\u003cp\u003eNo — this is the Marine Care tier, calibrated to 50 or 100 ppm resolution. Red Sea's Magnesium Pro kit is a separate, higher-resolution product for reef keepers chasing tighter control.\u003c\/p\u003e","brand":"RedSea","offers":[{"title":"Default Title","offer_id":54774154559779,"sku":"RED349","price":45.5,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0972\/7236\/5347\/files\/RED349.png?v=1772078881","url":"https:\/\/nicksaquariumoceanariumterrarium.com.au\/products\/red-sea-marine-care-magnesium-test-kit","provider":"Nicks Aquarium Oceanarium Terrarium","version":"1.0","type":"link"}