How to Raise Calcium in a Reef Tank
Calcium chloride is the fastest fix; two part systems maintain it. Never raise more than 50 ppm per day, and if calcium will not hold, test magnesium before dosing more.
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Steps Test magnesium first: below 1250 ppm, calcium will not stay in solution. Fix magnesium, then calcium. Calculate the exact dose for your water volume with the calculator below. Dose max 50 ppm per day into high flow, away from coral tissue. Retest after 30 minutes of mixing before any second dose. ReefMath is a calculator, not a substitute for testing. Always confirm with your test kit. Safe daily limits are built in: 1.4 dKH, 50 ppm calcium, 100 ppm magnesium.