Reef aquarium care · KM-001
Reef Aquarium Calcium Supplement Refill
Two measured pack sizes
Reef calcium prepared from a dry refill.
Choose a measured 300 g or 500 g refill, add water as directed and dose from your aquarium test results.
Choose your refill
More calcium for a lower cost per dose.
The 500 g value refill costs about 10% less per gram than the standard size.
Selected product
300 g Standard Refill
$12.00 plus shipping · Out of stock
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- Active ingredient
- Calcium chloride dihydrate
- Prepared strength
- Approximately 160 mg/mL calcium
- Supplement type
- Calcium only; no alkalinity or magnesium
- Origin
- Prepared in Australia from imported ingredients
Water is not included. Follow the directions shown for your selected pack size.
Why reef tanks need calcium
Hard corals and coralline algae use calcium as they grow. Regular testing shows whether your aquarium is consuming calcium and helps you make measured corrections without unnecessary dosing.
A calcium-only supplement
This product supplies calcium; it is not a combined alkalinity or magnesium supplement. Test calcium, alkalinity and magnesium, and adjust each deliberately. Do not mix concentrated calcium and alkalinity supplements together.
How to use it
- Read the complete directions before opening the refill.
- Add suitable water in the order and volume stated on the label.
- Allow the preparation container to cool fully before final preparation and use.
- Follow the supplied dosing table, then retest your aquarium.
Prepare the full refill according to its pack-size directions before using the guide below.
| Target increase | 100 L aquarium | 250 L aquarium | 500 L aquarium |
|---|---|---|---|
| 5 mg/L | 3 mL | 8 mL | 16 mL |
| 10 mg/L | 6 mL | 16 mL | 31 mL |
| 20 mg/L | 13 mL | 31 mL | 63 mL |
Test first, make adjustments gradually and retest. These figures are a dosing reference for the prepared solution, not instructions for correcting an aquarium without testing.
Calculate for your aquarium
Use your actual water volume and a current calcium test to estimate a prepared-solution dose and its value per dose.
Raises calcium by 10 mg/L in 100 L. The 500 g Value Refill provides about 133 equivalent doses at approximately $0.13 each, based on its $17.95 price excluding shipping.
Calculator results are estimates for the fully prepared solution at approximately 160 mg calcium per mL. Confirm actual water volume, test first, make larger corrections in stages and retest. Never add the dry refill directly to the aquarium.
Use and care
- Test your aquarium water before deciding whether calcium adjustment is needed.
- Keep the refill tightly closed and dry until preparation.
- Read the preparation directions before adding water.
- The preparation container becomes hot; allow it to cool completely before use.
- Never add the dry refill directly to your aquarium.
- Keep out of reach of children and animals.