Magnesium Dosing Calculator

This calculator can be used to estimate the amount of additive needed to reach the desired level of a specific element in the water.


Do not dose all at once. Doing so can cause extreme changes in water chemistry.  To prevent stress the maximum daily increase to calcium should be less then 20 ppm.  Use smaller amounts for multiple days to make gradual changes.

Any concentrates listed below must be reconstituted strictly following the manufacture's instructions.  Be careful when you use additives, always follow the instructions for the product and test your water on a regular basis.  WARNING: Certain Brand's alk supplements also contain trace & other elements

WARNING: You should be very careful about the kinds of products or chemicals put into your aquarium. Many of these products require keen knowledge of how they interact with your aquarium and saltwater. All of the products presented should be used with full knowledge of their capabilities and limitations as many of these products may add more than just either Calcium, Alkalinity and/or Magnesium. If you don't know what a product does, don't use it. Consult your manufacturer. Given the variability of their granular size, powdered products conversion between volume and weight are approximations; for safety, use less than the calculated amount and measure the effect before adding the rest. Although every effort has been made to obtain accurate results and recommendations we can not assume responsibility for any problem related to the use of this calculator.

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