Reef Octopus 10" KS250 Nilson Kalk Reactor
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Item #: CV-OCT-KS250
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Reef Octopus KS250 Nilson Kalk Reactor

Footprint: 12.6″ x 12.6″ | Body Diameter: 10″ | Height: 26″
Requires control timer and feed pump

    Raise or Stabilize PH
    Supplements Calcium and Alkalinity
    Binds Phosphates
    Silent Operation
    Solid Construction
    3/8" quick connect fittings

Gently mixes your calcium hydroxide

Reef Octopus Kalk Stirrer (Nilsen Reactor) carries a high torque low RPM motor that effectively, silently and gently mixes your calcium hydroxide (kalkwasser).  This method is not only ideal but is also the safest way of dosing the freshest possible kalkwasser to your reef system. The Reef Octopus Kalk Stirrer is designed to keep the  undissolved particles at the bottom of the reactor chamber while always leaving the clear highly saturated kalkwasser liquid at the top.  Adding kalk powder couldn’t be easier with just a few twists of the large thumb screws  releasing the seal-tight lid for quick and easy kalk refills.
No need for pesky Powerheads

No need for pesky powerheads that randomly need to be cleaned or replace and no more risky dosing with large vats of lime water which take up valuable space. You will never have to worry about premixing or clogs again when using our new innovative and efficient Kalk Stirrer (Nilsen Reactor) which are extremely easy to use and salt-water safe, making them simply the most economical and best kalk reactor out there.

*The Kalk Stirrer uses a 20w motor that has a lifetime of about 1500 hours. Please don’t run unit continuously.

- Kalk Stirrer Body with Stirrer Pump
- Quick Connect Input and Output: 3/8″

- Kalkwasser
- Water Feed Pump that will deliver water through the reactor
- Timer
- RO Tubing

Warranty - 1 year warranty on reactor body

Installation Instructions

    Place the reactor in a location where the outlet is higher than the sump. The quick connect outlet is where the kalkwasser will drip from and typically hung over the sump in a high flow area away from any pumps. The output must flow downhill to the sump area.

    Connect the feed pump from your top off container to the Kalkwasser reactor with 3/8 RO tubing. Peristaltic pumps are preferred due to the high level of accuracy and anti siphon characteristics. (If you are using a peristaltic pump then skip to step #4)

    If you are using a feed pump like Tom’s Aqualifter then the input tubing should be placed in your reservoir with RO/DI water. Connect the outlet of the pump to a short piece of 3/8” tubing and install a tee fitting with one end securely mounted several feet above the water level of your top off reservoir and the other going to the reactor. The tee is placed in the line to create a siphon break. You may also use a small pump such as a maxijet modded with a fitting on the output to feed water to the reactor. You will have to use a check valve in the line to prevent any back siphoning into your reservoir.

    The Kalkwasser reactor should be filled 2/3 of the way with RO/DI water.
    Add enough kalk powder to fill the reactor with approximately 3⁄4 – 1cup of kalkwasser. The idea is that the twin blades create a slow motion that gently disturbs the kalk in to solution. (Too much kalk will place stress on the motor and can cause pre-mature failure) Allow the solution to settle for 15 minutes prior to turning the reactor on. Now you are ready to plug the reactor’s transformer into a power source and begin to dose saturated Kalkwasser to your aquarium. The stirrer should be set on a controller to run ever 2 hours for approximately 10-15 minutes. Do not run these units 24/7.


    The addition of a saturated solution of Kalkwasser is considered the first method of supplying the reef aquaria with Calcium and Alkalinity while maintaining a high PH. Your new Octopus Kalk Reactor gently stirs powdered kalkwasser into RO/DI water creating a clear super saturated form of Lime water aka Kalkwasser. Due to its high pH of 12.4 a slow addition is required to avoid a dangerous rise of the pH value in the aquarium. An important advantage of the so called “Kalkwasser-method” is the precipitation of phosphates.
    Common ways of Automating your top off/ kalkwasser Dosing

    Via ATO- Simple plug your feed pump to the ATO (Auto Top Off) Units controller and saturated kalk will dispense when your tank need replenishment after evaporation. Via Timer or Controller- Estimate your daily evaporation and the time it takes for the pump to replenish the levels (remember that Seasonal changes will change your systems evaporation rate and the setting will have to be adjusted.) To avoid flooding, you should calculate a safety reserve and replace only two third of the evaporated water with Kalkwasser. This time is adjusted at the time switch. It is also possible to dose in several intervals to avoid a pH increase. It ideal, if you add the Kalkwasser during the night, when the pH in the aquarium drops.

    Warranty and contact information
    This Reef Octopus product is warranted for a period of one year from the date of purchase against defects in materials and workmanship. CoralVue will provide necessary parts and factory labor to repair or replace any failed components. The Buyer is liable for properly packaging the equipment and shipping cost for the initial return for repair. Return shipping cost is covered by CoralVue if service is needed within the warranty period. Equipment damaged due to accident, neglect, abuse, misuse, natural or man-made disasters is not covered by this warranty and the buyer will be contacted with cost and approval for repair. If you have any questions or issues pertaining to this product please contact: support@coralvue.com Liability In no event will Reef Octopus/CoralVue be liable for any lost livestock, profits or any special, indirect or consequential damages due to loss from use.

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