Tunze Osmolator Calcium Dispenser 5074

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Due to their growth, corals and algae consume the calcium dissolved in the water. The deficit caused can be compensated by the use of a calcium dispenser filled with calcium hydroxide and water. Conventional plants consist of large tanks with stirrers used to keep the milk of lime in constant movement, which however are bulky, require a lot of maintenance, and are expensive.

TUNZE Aquarientechnik GmbH has developed an inexpensive device to be operated in combination with the Osmolator 3155 or Osmomat 5024, which is able to produce the kalkwasser that is discharged into the tank continuously at a constant pH value. Together with the constant water level regulator, the so-called Osmolator, consisting of a metering pump and a storage container, the ideal solution was found.

By means of a screw, the Calcium Dispenser 5074 is easily fitted to the storage container of the Osmolator, and is attached between the hoses.


During the metering process, the fresh water automatically mixes with the calcium hydroxide in the dispenser. Thus, without an additional pump and stirrer, saturated kalkwasser is produced which is pressed into the tank by the metering pump. This process is repeated automatically with almost no servicing required. The consumed calcium hydroxide only has to be refilled, i.e. approx. 15 to 60 grams (.52 to 2.1 oz.) per week as needed. Refilling is done in next to no time. Unscrew the cover; fill in the calcium hydroxide; screw on the cover; shake the unit; and after a few minutes the plant with the automatic refill system continues to operate highly effectively, and it is fitted safely in the storage container, preventing any water damage.

Dimensions: 14" H x 3-1/4" D

Product Manuals & Documentation

Tunze Osmolator Calcium Dispenser 5074

Owner's Manual available for download in Adobe PDF file format

Manufacturer Info

For forty-five years the name TUNZE® has been synonymous with aquariums. Many products and components which we have developed in the course of time are now standard features of aquarium technology today. This confidence in TUNZE is no coincidence. The company has remained true to its philosophy right from the beginning, researching water biotopes all over the world to develop components which enable natural water conditions in the closed environment of an aquarium. In the implementation of know-how, effectiveness and efficiency, TUNZE® takes the lead in environmental compatibility. Their motto is: quality and reliability. These values are upheld with well thought-out and precise tool making by highly qualified experts. The brand names of TUNZE® and Turbelle® meet the expectations of the seal of quality; Made in Germany. Many of the products shown in this catalogue are protected by national and international patents.


Manufacturer`s Warranty: 1 year from date of purchase.



Experience Level: Expert


I have had this item and the Tunze top off system for three years. It is well made, reliable and the design is sophisticated. The only drawbacks are: 1. Other reviewers are correct. It would benefit from some sort of stirring mechanism. I'm toying with the idea of fitting a small pump activated by a timer to stir the contents briefly once a day. 2. It is important to keep the optical water sensor clean. this is mentioned in the directions, but one's memory can fail. The back-up high level sensor will save you, but it too should be periodically checked for proper operation.

3 out of 4 found this review helpful

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Experience Level: Intermediate

OK for some...but.

I bought this as an easy way to dispense Kalkwasser in conjunction with the Tunze Osmolator topoff unit I purchased. Basically, water enters the dispenser from the bottom, and water exits into your sump/tank thru the top. After about a week I took mine out and bought a Kalkwaser stirrer instead for a lot more money.......the issue? My tank is an SPS type reef and it uses a lot of calcium..so this product was not up to the task. I believe that this would work well in an LPS, mixed (Soft/LPS), or soft coral type tank where the rate of calcifiction is less. Anyone wanna buy a slightly used kalkwasser dispenser?

9 out of 13 found this review helpful

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