Octopus 4" Calcium Reactor by Coralvue is a great reactor for a small to mid sized tank. 

Octopus 6" Calcium Reactor by Coralvue is a great reactor for a mid to large sized tank.  It will supplement alkalinity and calcium in your saltwater reef tank aquarium.

Octopus 6" Calcium Reactor by Coralvue is a great reactor for a mid to large sized tank.  It will supplement alkalinity and calcium in your saltwater reef tank aquarium.

The Octopus CR1000 calcium reactor is rated for up to 100 gallons and comes with a water blaster pump and 3 year warranty.

The Octopus CR3000 calcium reactor is rated for up to 400 gallons and comes with a water blaster pump and 3 year warranty.

Super Reef Octopus or SRO Calcium Reactors are the best in the industry.  With a new water blaster pump and large reaction chambers make them ideal for large tanks. 

Super Reef Octopus or SRO Calcium Reactors are the best in the industry.  With a new water blaster pump and large reaction chambers make them ideal for large tanks. 

Korallin C1502 Calcium Reactor with Eheim pumps are quiet and efficent.  Korallin reactors are some of the most efficent and best calcium reactors on the market.

Korallin C1502 Calcium Reactor with Eheim pumps are quiet and efficent.  This package includes the CO2 regulator and media along with the Korallin reactor.

Korallin C1502 Calcium Reactor with Eheim pumps are quiet and efficent.  This package includes the CO2 regulator, tank, and media along with the Korallin reactor.

The Milwaukee PH MC122 controller is a great solution for controlling and monitoring the PH on your calcium reactor.  Calcium reactors work best when monitored by a controller and PH probe. 

CO2 regulator by Milwaukee Instruments includes solenoid valve and bubble counter.

Deluxe CO2 regulator by includes solenoid valve and bubble counter.

Deluxe CO2 regulator by includes solenoid valve and bubble counter.

The AquaMaxx Star Nano Calcium Reactor is a new design that will allow maximum performance for CO2 consumption and good up to 75 gallons.

AquaMaxx Calcium Reactors use an upflow design to mix saltwater, calcium carbonate and CO2 inside a reaction chamber to eliminate the need for daily two-part dosing.

AquaMaxx Calcium Reactors use an upflow design to mix saltwater, calcium carbonate and CO2 inside a reaction chamber to eliminate the need for daily two-part dosing.

Bubble Magus calcium reactors are a quality product at a great value.  Bubble Magus products are made of high quality acrylic.

Bubble Magus calcium reactors are a quality product at a great value.  Bubble Magus products are made of high quality acrylic.

Bubble Magus calcium reactors are a quality product at a great value.  Bubble Magus products are made of high quality acrylic.

CaribSea A.R.M. Aragonite Calcium Reactor Course Media is the best option for media in your calcium reactor. 

CaribSea A.R.M. Aragonite Calcium Reactor Original Media is a good option for reactors.  However course is generally sold since it is less likely to "melt".