Deltec KM500 Kalkwasser Stirrer

Deltec KM500 Kalkwasser Stirrer

• Helps to Maintain Calcium, Alkalinity, and pH
• Ideal for Use Stand-Alone or with Calcium Reactors
• Designed for In-Sump or External Installation

The Deltec KM500 Kalkwasser Stirrer is designed to produce a saturated solution of kalkwasser, also known as limewater, for maintaining calcium, alkalinity, and pH levels in reef aquariums.

The KM500 can be used as a stand-alone supplementation method or alongside a calcium reactor to help counteract low pH. Its compact design allows for installation in or near your sump, making it a practical solution for automated kalkwasser dosing.

Why Use a Kalkwasser Stirrer?

A kalkwasser stirrer provides a clean, controlled way to deliver saturated kalkwasser to a reef aquarium. Kalkwasser, also known as limewater, helps replace calcium and alkalinity consumed by corals, coralline algae, and other calcifying organisms, while also helping support a higher, more stable pH.

How Does It Work?

Instead of manually mixing kalkwasser in a top off reservoir, the stirrer keeps calcium hydroxide contained in a dedicated chamber. Fresh RO/DI water passes through the reactor and becomes saturated before being added to the aquarium. This helps keep the top off reservoir cleaner, reduces manual mixing, and limits exposure of the kalkwasser solution to air.

Methods for Use:

Auto Top Off
Connect your automatic top off system to your kalkwasser stirrer so evaporated water is replaced with saturated kalkwasser. This is a simple and popular setup that allows kalkwasser dosing to happen automatically without the need for a dedicated dosing pump. Because delivery is based on evaporation, the amount dosed can vary from day to day, so regular monitoring of pH, calcium, and alkalinity is recommended.

Dosing Pump
While many aquarists connect a kalkwasser stirrer to an automatic top off system, the most consistent approach is often to feed the stirrer with a dosing pump. A dosing pump allows a fixed amount of kalkwasser to be delivered throughout the day, independent of changes in evaporation. This provides more predictable supplementation and helps reduce the risk of pH, calcium, or alkalinity swings.

Installation & Maintenance

Connect the top off or dosing pump to tap No. 8 on the inlet side of the stirrer. The outlet from the stirrer should gravity drain into the sump. To prevent backflow, install a check valve between the top off pump and the stirrer.

Using the Kalkwasser Stirrer

1. Remove the stirrer head from the main tube.
2. Fill the tube with calcium hydroxide:
   • KM500: approximately 150 g
   • KM500S: approximately 500 g
3. Add approximately 1.5 liters of RO/DI water and stir manually.
4. Reinstall the stirrer head, start the stirrer, and allow the chamber to fill.
5. Once the stirrer is completely full, stop the water supply and allow the calcium hydroxide to settle.
6. When approximately two-thirds of the water column is clear, restart the water supply and adjust it to a fast drip.

Important Notes

• The stirrer outlet should always be positioned higher than the sump to prevent the stirrer tube from overfilling.
• The outlet hose should not end below the water surface.
• Do not use excessive water flow. High flow can make the water cloudy and may cause calcium hydroxide to enter the sump, especially during longer dosing periods.
• Check the stirrer outlet regularly for blockages and clean it when necessary.
• Do not use aquarium water to operate the stirrer.
• If the stirrer has been stopped for an extended period, manually stir the calcium hydroxide before restarting the stirrer motor.

Maintenance

When the calcium hydroxide has been depleted, as indicated by a reduced pH value, switch off the pump and disconnect the tubing from the stirrer.

Clean out any remaining calcium hydroxide, refill with fresh calcium hydroxide, and repeat the setup steps.

Specifications

• Model: KM500
• Recommended Aquarium Size: Up to 400 gallons
• Production: 1.3 gallons kalkwasser solution per hour
• Approx. Water Capacity: 5 liters
• Kalkwasser Capacity: 150 grams
• Dimensions: 5" x 8" x 19"
• Power: 7.5V / 3W

What's Included?

Deltec KM500 Kalkwasser Stirrer