OCTO CalReact 200, Calcium Reactor w. VarioS 4 pump

Out of stock


OCTO CalReact features high-quality cast acrylic body construction, a PH probe holder to allow constant monitoring of water alkalinity (PH level) with the use of a PH probe (sold separately), a built-in bubble counter for CO₂ flow rate calculation, reverse water flow for CO₂ recirculation to maximise contact time with the coral media which produces CO2. Powered by our VarioS DC pump which features a pinwheel impeller, a detachable controller, high quality ceramic shaft and bearing to reduce wear and tear, and the latest variable speed flow technology for refined control, enhanced performance, energy-efficiency and safer operations. Unlike the vast majority of circulation pumps which uses alternating current (AC), our VarioS pump boasts several key advantages over traditional AC pumps, namely, higher energy efficiency, safer operations at a working voltage of 24V and most notably, the variable speed control to adjust the ideal mix of air and water flow into the skimmer.

Available in 3 models – CalReact 140, CalReact 200 and CalReact 220.




  • For aquariums up to 200 gallons

  • Variable speed, Apex ready VarioS 2 Pump

  • Reverse flow and CO2 recirculating design

  • Auto fill bubble counter

  • Probe holder w/ plug (pH probe NOT included)

  • Easy to remove lid

  • Precision effluent control valve

  • 1/4" quick connect fittings

Technical Specs:

  • Body Size: 5.5in

  • Footprint: 12.2in x 9.1in

  • Total Height: 23in

  • Media Capacity: 3.8L (1gal)

  • Inlet Size: 1/4in

  • Max Feed Rate: 150GPH

Note: This is not a pressure-rated pump. This pump is not for second floor applications or to feed Beckett or downdraft skimmers where constant pressure is required.

How it works: A calcium reactor is essentially a chamber full of Aragonite which is natural form of carbonate mineral, or commonly known as crushed hard corals. Aquarium water is circulated through this chamber along with carbon dioxide (CO2). The CO2 lowers the pH in the chamber to an acidic level which dissolves the carbonate minerals into the aquarium water. In addition to dissolving the carbonate minerals, this process also dissolves nearly all the minerals and trace elements the coral needed in order to grow.

Automated Calcium and Alkalinity supplementation – When set up properly with external controller and probe. These perimeters can be pre-set with very little monitoring and maintenance.

Features & Benefits

  • Reverse flow and CO2 Recirculating Design

  • Built-in bubble counter for monitoring of CO₂ flow rate/drip rate?

  • Probe holder with plug*

  • Easy-to-remove lid – change to: Easy maintenance

  • Removal lid for easy maintenance

  • Precision effluent control valve

  • High quality handmade solid cast acrylic construction

  • Controllable and variable speed DC pump for energy-efficient and silent operations