KNOP Calcium Reactor HD

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  • for aquaria of 150 to 350 gallons (600–1500 l)
  • constant calcium values above 420 mg/l
  • constant carbonate values above 8° dKH
  • small CO 2 consumption
  • includes EHEIM pump
  • internal circulation 1200 times per hour
  • bubble counter included
  • includes CO 2 safety valve
  • automatic release of false gas
  • connector for optional pH probe
  • H x W x L = 21 x 8 1/4 x 15 AS7207
The KNOP calcium reactor model HD has been released to the market in 1994 as the “big brother” of the model C. Because of its reliability, the stable construction, the easy operation and the affordable price it has become one of the most frequently sold calcium reactors in this size category.

Product Manuals & Documentation

KNOP Calcium Reactor HD

Owner's Manual available for download in Adobe PDF file format



Experience Level: Intermediate

An ok product

I bought this at the recomendation of a WWM guide and to be honest I was looking at this to begin with as it is my second Knop HD. I wanted to go with the S-IV this time, but at Wet Web Media's recomendation I ordered this one. I had an aweful time getting the output tube connection to the pump to stop leaking. Just horrible how long it took be messing with teflon tape before I finally hijacked some of the other o-rings from the spare parts that come with the eheim pump. Only then did it stop leaking. As for the rest of the components, they seem well made, but the instructions lack much to be desired as this is a german product with some cheap english translation.

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