KM-200 Magnetic Kalkwasser Mixing Reactor

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No More Broken Stir Bars or Replacing Expensive Mixing Pumps!

Kalkwasser is one of the oldest and reliable ways to add calcium and alkalinity from a single solution and using a reactor makes the addition of a kalkwasser solution easier. The IceCap KM-200 Magnetic Kalkwasser Reactor uses a magnetic stirrer to accomplish the mixing of the solution, which means you will never have to clean or replace an expensive mixing pump ever again, and also cuts the maintenance down to bare minimums. 

  • Adjustable Speed Magnetic Stirrer
  • Push-Connect Fittings
  • Made of PVC and Acrylic
  • Quick-Fill Cap For Adding Kalk
  • Gravity Drain System For Consistent Doses
  • Sealed Environment Keeps the Kalkwasser Potent 


Perfect for Reef Tanks Up To 300+ Gallons

The Kalkwasser powder is relatively inexpensive, is super concentrated and can simply be mixed into your top-off water. Additionally, the elevated pH of the resulting kalkwasser solution and CO2 reducing properties help to maintain a more desirable and stable pH of 8.3 inside your tank. The use of the IceCap Kalk Mixer will ensure maximum concentration with each dose to your aquarium and reduce the need for frequent manual addition and mixing of the solution.


How Does it Work?

Simply connect the IceCap Kalk Mixer to any freshwater reservoir with the use of an Auto Top Off unit or dosing pump. Kalkwasser powder is then added to the mixing chamber via the handy quick-fill cap. The adjustable speed motor should then be attached to a timer or controller and set to periodically mix the solution inside the reactor a few times per day. When freshwater is pumped from your ATO reservoir into the reactor, the freshly mixed and highly concentrated Kalkwasser solution is pushed out and into your aquarium. When adding kalkwasser to any aquarium, it is best to use a pump with a slow flow rate. Due to the high pH of the solution, you must add kalkwasser slowly and in small amounts, typically multiple times per day. Most ATO systems on the market will fit the flow rate needs of the reactor very nicely because of the small and frequent dosages of freshwater.


What else is needed to get a Kalkwasser Reactor Running?

Probably the most obvious things are going to be the reactor and some high-quality kalkwasser. There are a few things that are not as obvious though which are listed below and not included with the Ice-Cap KM-200 Magnetic Kalkwasser Reactor. 

Kalkwasser - This is the part that is actually going to be going into your aquarium and we highly suggest using a high-purity kalkwasser solution. Many kalkwasser supplements on the market today have impurities and high amounts of aluminum in them, which can be harmful to your reef tank. Especially when it comes to using kalk in a reactor the higher the grade will mean longer intervals required between maintenance and longer-lasting equipment. 

A Slow Flow ATO System - In most cases, a simple low-flow pump and a timer will be a great solution to an ATO system but there are a few others on the market that use optical eyes and float valves that work great. Kalkwasser has a high pH and if added to fast or too much at once could cause the pH of your aquarium to raise over desired levels. The ATO system will essentially plug into the input side of the reactor and push the water through the settled kalkwasser solution allowing the clear amount at the top to flow into your aquarium. A couple of good ATO system is a BRS 50mL Doser and a digital timer (or aquarium controller) or a Tunze Osmolator which can have the pump's flow adjusted by opening the controller housing and simply turning a screw. 

Drain Tubing - The IceCap Magnetic Kalk Reactors uses a 1/4" push-connect fitting that can be connected to traditional RO style tubing. With Kalkwasser solutions we like to use a clear or natural line to see any potential clogs forming, however many reefers do like to use a colored tubing for easy identification of the solution inside. 

Digital or Analog Timer - The magnetic stirrer that is included in the base will need a power source, and using a simple timer or aquarium controller system, you will be able to control when the solution is mixed. We highly suggest a digital timer if you do not use a controller, but an analog timer can work for telling the reactor to mix the solution a few times a day.  To keep the kalkwasser solution mixed properly, just run the magenetic stirrer for a minute or two 3-4 times a day. We suggest trying to keep the mixing to a minimum, and avoiding dosing during or immediately following a mixing cycle.



Footprint - 9" x 9"

Height - 25"

Body Diameter - 8"

Total Volume - 3 Gallon (approx)*

Input Tubing Size - 1/4" O/D (RO Style Tubing)

Output Fitting Size - 1/4" Push-Connect

*Note: Reactor should not be completely filled with kalkwasser powder. Kalkwasser should be added based on the evaporation rate of the system and the refill interval. We recommend a 2 week interval for service and refills and that the reactor should not be filled more than approximately 25-30% full. 


What's Included?

1x KM-200 Magnetic Kalkwasser Reactor Body with Lid

1x Variable Speed Power Supply

1x 1/4" Push-Connect Ball Valve 

1x 1/4" Barbed Coupler


Note: Kalk Mixer motor is not suitable for continuous use and should not be run constantly. Necessary ATO system, calcium hydroxide (kalkwasser), dosing pump and timer/controller are required and sold separately. Reactors are not submersible.

More Information
SKU 212575
UPC 6920042802360
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Product Questions

Hi, Does the icecap km-200 Kalk stirrer output need to be higher than the sump like a gravity drain or can the feed pump actually push the output water up however high under pump head pressure? I’m trying to locate a Kalk stirrer away from the sump possibly under the sump, so the output would have to flow up
Question by: John Joseph on Jan 18, 2020, 11:39 PM
Hey there!

It does not need to gravity feed, the ATO pump should be able to push it through. Just make sure you do not exceed the head height the ATO pump can handle.
Answer by: Thomas Billington on Jan 22, 2020, 2:38 PM