Knop C Calcium Reactor

For many of us reef hobbyists, dosing of required calcium supplements presents it's own set of chores and headaches. Measuring, mixing, dripping, etc., all add up to a daily routine that can be safely and efficiently eliminated by adding, you guessed it, a kalkreactor! Sure, there are many brands and versions of reactors out there and they all share one common denominator -- CO$T.

Yup, there ain't a "cheapie" reactor out there, so choosing the right model to suit your individual needs and requirements can be not only confusing, but expensive.

Enter the Knop "C" Kalkreactor. Designed by leading German aquarist, Daniel Knop, (he wrote "the" book on clams), this little device packs a very big punch! It's delivery of calcium and other necessary minerals to our water chemistry is accomplished via a very simplified design that is set up and running in about 1/2 hr!

Although the manufacturer and distributor both recommend Koralith media, any good grade of aragonite or other commercial brand of calcite will work. The grain size of media for optimum dissolving is 2 to 3mm. Stay away from finer grain sands as the media tends to form "slush" at the bottom of the unit and can create a slow-down of water flow (back-pressure).

The unit as I received was packaged well and intelligently arranged. However, the delivery guy musta drop-kicked my box as the top housing was cracked and required replacement. At this point I'd like to compliment Mr. Robert Keane, the Distributor. His immediate attention to my problem resulted in a new part being delivered within the next 2 working days and I was none the worse for worry!

Following the directions for set-up and calibration was easy and straight-forward. The Knop uses an Eheim recirculating pump and does require an additional drive pump located either in your sump or from the show tank itself (if you are not using a sump). The design utilizes very little Co-2 to dissolve the media and a 5# bottle of Co-2 can last up to 6 months! Because of the recirculation feature, Co-2 consumption is minimized.

Co-2? Howz that figure in? Well, you must dissolve the calcium media into solution in order for your animals to absorb it into their tissues. The Co-2 lowers the pH inside of the reactor to around 6.5 (optimum). At lower pH (acidic) the aragonite/calcite/Koralith media dissolves into the water chemistry and boosts the Ca content immensely. Levels of +400ppm and dKH of 9 to 11 degrees can be achieved by doing NOTHING once the reactor is operating correctly! This calibration revolves around the bubble count of Co-2 that is injected into the reactor body. This is accomplished by connecting a pressure bottle of Co-2 gas through a magnetic solenoid valve, directly to the reactor's bubble counter. I set the count at 65 drops per minute to achieve that 6.5 pH on my setup. Yours may be different.

The effluent is controlled by a little valve that attaches to the hose running back to the tank/sump. This valve automatically regulates the return flow to the aquarium and require little to no maintenance.

All in all, this unit surpasses those costing many $$ more and features a very small footprint for those crowded under-cabinet installations! The Knop is a free-standing arrangement that can mount beside, behind or even on the wall behind the aquarium. I have had mine now just about 1 year and cannot even image running a reef system without it! Corallines like you've never dreamed and water quality that's hard to surpass.

The biggest problem with the Knop is FINDING one! I have only seen the unit advertised in FAMA magazine by the distributor (wholesale sales only). I'm sure that if you inquire, Mr. Robert Keane could provide those retailers that carry the reactor. You can E-Mail him at Bobkeane@aol.com, leave a message at (404) 768-1147 or FAX to him at (404)761-6800. A real gentleman, he WILL get back to you.

From the before and after photos I have included with this review, notice the corallines growing on the rock and glass sides of my tank. This reactor is SO efficient that I have only refilled it once in 1 year! Hat's off to professionelle Meeresaquaristik and Mr. Daniel Knop!!!

My rating? 10 out of 10, bar none! Do I miss dripping kalkwasser? What do you think? -- Review Dateline 1999