Calcium Supplement Calculator

Enter your aquarium water volume, current and desired calcium level, and then select your additive of choice to find out how much you need to add to reach that desired calcium level.

Total System Volume

Current Calcium Levels

ppm

Desired Calcium Levels

ppm

Product

Results:

Calcium Dosing Tips

It is recommended to maintain calcium levels at 380 - 450 ppm in a reef aquarium. Not all calcium additives are created equal, and it is important to refer to the manufacturer's instructions before adding anything to your aquarium. Please reach out to our Customer Service team anytime to speak with a reef aquarium expert.

Before You Dose

Maintenance vs. Correction: A small maintenance dose is added daily to replenish calcium that is used by corals and to maintain stable calcium levels in your aquarium. Large correction doses are used to adjust calcium levels that have fallen out of an acceptable range.
Large corrections: Spread the dose over a few days when adjusting more than 50 ppm. For example, if your required adjustment is 120 ppm, divide the calculated dose by three and add equal amounts to your aquarium over three consecutive days. Test your water chemistry in between doses to monitor your aquarium's response.
Mixing: Fully dissolve powdered calcium supplements in RO/DI water before adding them to the tank as instructed by the manufacturer.
Where to add: Dose liquids slowly into a high-flow area, away from pumps, heaters, and other equipment to reduce precipitation.
Spacing supplements: Do not add calcium and alkalinity back-to-back. Leave at least 20 to 30 minutes between doses to avoid precipitation.

After You Reach Your Target

Slow & steady: Once your target calcium levels are reached, make small daily doses to replenish calcium that is consumed by your corals.
Test to dial in: Test calcium daily until consumption and dosing are matched, then switch to weekly or even bi-weekly checks.
Expect changes: As corals grow, consumption rises. You may need to increase daily dosing every few months to keep up with your tank's demand.