Guide topic
Reef Chemistry
Plain-English, source-cited guides to keeping reef water in balance.
Guide
Why dose magnesium before calcium and alkalinity
If Ca and Alk won't hold, low Mg is usually why — the chemistry, the dosing order, and the targets.
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Guide
Reef tank target parameters by tank type
Ca, Alk, Mg, pH, nitrate, phosphate, and salinity targets for SPS, mixed, and LPS/soft tanks.
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The app for this
Reef: Aquarium Chemistry
Log a test and get magnesium-first guidance plus paired calcium + alkalinity doses for your exact tank and supplement — with safe daily-rise caps. Pay once, no subscription, no ads, fully offline.