Reef aquarium calcium dosing calculator

Calculate a calcium chloride stock solution using anhydrous, dihydrate or hexahydrate salt and match it to your aquarium volume and dosing container.

How this calculator works

Different calcium chloride hydrates contain different proportions of calcium. Select the exact product form on the label so the calculated dry mass matches the material being used.

Common questions

Why does the hydrate form matter?

Water bound in the crystal changes the calcium percentage, so anhydrous and hydrated calcium chloride require different masses.

Can calcium be corrected in one dose?

Avoid abrupt large changes. Divide substantial corrections and measure calcium and alkalinity between doses.