Dosing reagents

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Dosing is where the math on this site pays for itself, because the right product is a direct function of how much alkalinity your tank consumes per day — and that number is small. Once you know it, the decision is mostly about labor and cost per gram. The budget reality is that two-part is just chemistry: sodium bicarbonate or carbonate for alkalinity, calcium chloride for calcium, magnesium chloride and sulfate for magnesium. The budget tier is exactly that — Arm & Hammer baking soda, bulk food-grade calcium chloride, magnesium chloride flakes and Epsom salt, plus kalkwasser if you dose through top-off. It is by far the cheapest way to dose a reef, with one catch: check the hydration state on the label (dihydrate vs anhydrous calcium chloride, hexahydrate magnesium chloride) or the recipe math is off. The value tier is the same chemistry with that uncertainty removed: BRS pharma-grade soda ash, calcium chloride dihydrate, and magnesium mix, plus Red Sea's Foundation A/B/C powders, all sold in forms the published recipes are written around. The premium pick is Tropic Marin All-For-Reef: one bottle that supplies alkalinity, calcium, magnesium, and trace elements in balance, so you dose a single thing and stop chasing ions against each other. It costs more per unit of alkalinity than any DIY two-part, but it removes the part of dosing people get wrong. Whatever you pick, size the pack to demand, not to the tank's gallons: a lightly-stocked 120 can burn through less reagent than a packed 40-breeder. That's exactly what the precision sizing on our dosing calculators is for.

Last reviewed 2026-09-30