Rated 5.00 out of 5 based on 2 customer ratings
(2 customer reviews)


The CR612X2 DUAL chamber calcium reactor will hold 16 pounds of large grain media and is well suited for reef aquariums up to 300 gallons.

SKU: CR612X2 Category: Tags: , , , Product ID: 1716



  • 6″ diameter reaction chamber
  • 6” diameter secondary chamber
  • All cell cast acrylic construction
  • Key hole slot for lid removal
  • Full access to the reaction and secondary chambers
  • Micro ball valve effluent control
  • Sicce Syncra 1.5 pump circulation, bolted to base plate
  • pH probe port in lid
  • pH probe adapter included
  • Auto fill bubble counter
  • 18.5” x 8.5” foot print, 16” overall height
  • Comes with tubing harness shown in picture

Additional information

Check Valve

None, Add High Grade Check Valve for 19.99

Precision Needle Valve

None, Add Precision Needle Valve for 25.99

2 reviews for GEO CR612X2 Calcium Reactor

  1. Rated 5 out of 5


    I’ve been running this for a month now on my 180 gallon reef. Its been working fine so far, giving me consistent parameter readings. Very well built. Support via email has been excellent too!

  2. Rated 5 out of 5

    Lance Umansky

    I love this reactor! It’s build very sturdy, it was easy to put together. I’m the type that would rather have something all set to go out of the box with NO assembly at all. But even I was able to do this in maybe 15 mins. The screens on the bottom hold the media very well, and are also sturdy. I have large coral pieces in one chamber, and ARM (like gravel) in the other, and even the ARM does not fall through. The pump that comes with it is top notch. QUIET and restarts nicely if power goes out (important). Sometimes it takes a few minutes, to restart b/c of air that might be in the tubing, but it does restart no issue.
    NO leaks in the year I’ve been using it. I mention that b/c my former Ca reaction I had issues sometimes with small amounts of water coming out of the top lids. The probe access hole also is secure, no leak at all.
    I keep very steady Ca levels with this. Spot on. And when I have my condo ventilated, I have a tank pH of 8.2+ . I have a lightly stocked tank 110 gallons, fairly new. I keep a bubble count of 1 bubble per 8 seconds I believe, and a medium fast drip on the effluent, I’m always at 10dkH.
    Customer service is great.
    I was nervous about getting this, b/c it does have a cost to it of course. But the time it has saved from dosing and keeping up with trying to keep stable levels has more than paid for itself in time and hassle. Oh, and I even keep Mg levels at 1400 by adding Mg pellets to the chambers.
    Again, what I really like about the unit is the workmanship put into it, and just the overall quality, especially for the price.

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