Kalkwasser — Pure Calcium Hydroxide Powder 14 oz and 3.5 lbs for Top-Off Dosing - ESV

ESV Kalkwasser (calcium hydroxide powder) is a proven standard for maintaining calcium concentration and alkalinity in closed marine aquaria. It is one of the very few effective methods that adds calcium and alkalinity with a single product while maintaining pH. Commonly used in conjunction with auto top-off systems.

How limewater works

The calcium supplied is directly utilized by calcifying organisms (corals, coralline algae). The hydroxide ions readily convert dissolved CO2 into bicarbonate and carbonate ions — also directly used by calcifying organisms. That double action is what makes kalkwasser a complete single-product method.

Certified purity

ESV calcium hydroxide is extremely pure and meets American Water Works Association and Water Chemical Codex requirements.

Dosing

ESV does not publish a dosing chart on its product page. If you see a number elsewhere, it doesn't come from the manufacturer. Kalkwasser is commonly dosed through auto top-off water — write to us with your tank volume and calcium demand and we'll guide you.

Two sizes

• 14 oz (400 g) — the small jar, to get started or for small tanks.
• 3.5 lbs (1600 g) — the big jar, four times the powder for hungry systems.

Why buy at ReefSolution

Marine aquarium specialists in Laval: in-store advice and shipping across Canada. From the same ESV family:

• B-Ionic Calcium Buffer 2×16 oz — the liquid two-part calcium + alkalinity system.
• Liquid Carbonate Buffer — liquid alkalinity buffer.
• Calcium Chloride 800 g — to raise calcium on its own.

Frequently asked questions

What is kalkwasser?

"Limewater": calcium hydroxide dissolved in fresh water. Dosed into the aquarium, it adds both calcium and alkalinity with a single product while maintaining pH.

How do I dose ESV kalkwasser?

ESV does not publish numbered directions on its product page. The common practice described by the manufacturer is to use it with an auto top-off system. Write to us for a dosage suited to your tank.

Is ESV kalkwasser pure?

Yes — ESV calcium hydroxide meets American Water Works Association and Water Chemical Codex requirements.