K2R Calcium Reactor

The Advanced Reef Technologies K2R Calcium Reactor was one of the best calcium reactors on the market when I got it. By today's standards it is a little on the small side. It follows the traditional recirculating design. In this type of design the CO2 and water mixture is continuously circulated in the chamber through the calcareous media via a closed circulation loop.

New water from the tank enters the reactor via a feed pump (I use a MiniJet 404) which gets attached to a tee connector to the re-circulation pump (made by Eheim) at the bottom of the reactor. Water exits the reactor at the top which gets returned to the sump.

The reactor is fairly easy to operate since there are really only two adjustments that can be made, IE: the amount of CO2 being introduced into the reactor and the effluent flow rate exiting the reactor. Leaving the CO2 rate constant and increasing the effluent rate reduces the alkalinity while increasing the CO2 rate and leaving the effluent flow rate constant will raise the alkalinity of the effluent.

The K2R unit needs a little more than 8" x 8" floor space and stands about 19" tall.

Tuning the K2R is not always easy. I took almost 2 months before I found a setting that worked for my tank when I first got it. It is as follows: I keep the regulator at 5 PSI. The effluent flow rate is at 65cc/min, with a bubble rate of 120 giving me an effluent pH close to 6.4 to 6.5 at ~20 dKh. An effluent of 20 dKH is a little low but works for me, I would rather it be closer to 23 dKH.

A calcium reactor can also be made to maintain your Magnesium levels by adding dolomite to the reactor. It is suggested that you start at 2% of your media volume as dolomite. For myself that worked out to be about 2.5 to 3.0 oz of dolomite. Track your magnesium levels very carefully as to much can kill most critters in your tank. I try to keep my Mg levels at 1250 to 1350 ppm.