Seachem Kalkwasser

Seachem Kalkwasser is a high-purity calcium hydroxide limewater mix for marine aquarium keepers maintaining calcium levels close to natural seawater concentrations. It is designed for use in top-off water and can increase pH without directly affecting carbonate alkalinity.

Key Benefits

• Pure calcium hydroxide with high purity and solubility characteristics.
• Prepares kalkwasser or limewater solutions for direct calcium maintenance.
• Helps maintain calcium directly while supporting carbonate alkalinity indirectly.
• Can be used to raise pH without impacting carbonate alkalinity.
• An economical option for reef aquarium calcium supplementation.

How to Use

• Never add Seachem Kalkwasser directly to the aquarium.
• Mix the required amount with water, allow the solution to settle, then drip only the clear supernatant (top solution) into the tank.
• Do not allow undissolved material to enter the aquarium.
• Adjust the drip rate to maintain a stable pH of 8.3–8.4.
• Keep the container tightly closed and minimise solution-to-air contact to reduce calcium carbonate formation.

Dosage

• Add 3 g (1 teaspoon) to 4 L (1 gallon*) of water and mix to dissolve.
• When using pure water, prepare a fully saturated solution with 6 g (2 teaspoons) per 4 L (1 gallon*).
• Adding 4 L (1 gallon*) of saturated kalkwasser solution to 150 L (40 gallons*) raises calcium by 24 mg/L.

Suitable For

Marine and reef aquarium systems where evaporation rate and CO2 concentration allow kalkwasser to maintain calcium and support alkalinity. Kalkwasser can be an effective maintenance method, but it requires diligent monitoring and may be more challenging for beginners.

Compatibility

If additional calcium is required, use Reef Advantage Calcium™, Reef Complete® or Reef Calcium™. For carbonate alkalinity, use Reef Builder™ or Reef Carbonate™. Do not mix these products directly with a kalkwasser solution.

Frequently Asked Questions

Can I add Seachem Kalkwasser powder straight into my marine tank?
No. Never add it directly to the aquarium. Prepare the limewater solution separately and drip only the clear top solution into the tank.

How much Seachem Kalkwasser should I mix for regular limewater?
Mix 3 g (1 teaspoon) with 4 L (1 gallon*) of water. For a fully saturated solution made with pure water, use 6 g (2 teaspoons) per 4 L (1 gallon*).

What aquarium parameters should I monitor when using kalkwasser?
Monitor pH and carbonate alkalinity, and adjust the addition rate to maintain pH at 8.3–8.4. Magnesium concentration should also be monitored and maintained.

Will kalkwasser affect carbonate alkalinity?
It increases pH without directly impacting carbonate alkalinity, while kalkwasser solutions maintain calcium directly and carbonate alkalinity indirectly.

Why is there chalky build-up in my aquarium or plumbing?
Kalkwasser use can increase chalk build-up on substrate and plumbing surfaces. More frequent cleaning may be needed to keep aquarium equipment functioning properly.

Are there handling precautions for Seachem Kalkwasser?
Avoid contact with or breathing the dust. Do not eat it or get it in your eyes. If contact occurs, flush with water for 5–10 minutes; for eye contact, wash immediately with water and seek medical attention.