Calcium Calculator
Enter your aquarium details to calculate the amount of calcium supplement needed.
Start Slow: Recommended Dosage
Note: The values generated by this calculator are suggested starting points and should be adjusted based on your tank’s needs.
We recommend beginning with half the calculated dose and testing your calcium level 24 hours later. From there, adjust slowly as needed to reach your target.
Avoid dosing the full amount all at once. Sudden changes in calcium can destabilize water chemistry and stress corals. Instead, split the dose over 1–2 days or more for a safer, gradual correction.
Monitor pH closely during this process and avoid swings greater than ±0.20. Test your parameters daily until stability is achieved.
Keeping Calcium Stable
Keeping calcium stable is one of the most important parts of maintaining a healthy reef tank — but precision is key. This calculator helps you determine the appropriate dose based on your tank volume, current calcium level, target calcium level, and your preferred supplement brand.
How This Calculator Works
This tool is designed to help reef keepers dose accurately using trusted calcium products. By inputting your current and desired calcium levels, the calculator determines the amount of supplement needed based on your tank volume and the concentration of the product selected.
Supported Calcium Supplements
- - Brightwell Reef Code A: Balanced calcium solution with added magnesium and strontium to support skeletal growth.
- - Fauna Marin ELEMENTALS (Ca/Sr): Highly pure calcium and strontium additive designed for precise control in Balling Light systems.
- - Tropic Marin Balling Part A (Dry): A dry-mix calcium chloride formula commonly used in Balling dosing systems.
- - Fritz RPM Liquid Calcium Elements Part 2: A liquid calcium additive that also helps maintain ionic balance.
- - Ocean Blend Calcium: A simple, effective solution for reef tanks with moderate to high calcium demands.
- - ESV B-Ionic Component NO.2: The calcium portion of the B-Ionic two-part system, ideal for balanced calcium and alkalinity control.
- - Two Little Fishies C-Balance Part A: A two-part calcium and buffer system designed to replicate the natural ionic ratios of seawater.
When to Dose Calcium
Most reef tanks aim for a calcium range between 400–500 ppm. You should dose when your calcium levels drop below your target, especially in coral-heavy systems where consumption is high. Always test before and after dosing to confirm effectiveness.
Tips for Best Results
- - Always test calcium before and 24 hours after dosing
- - Monitor alkalinity alongside calcium to prevent ionic imbalances
- - Dose slowly and in increments to avoid sudden parameter swings
- - Shake liquid supplements thoroughly before use
- - Keep good records of your dosing and test results over time
