If you have a place to put one you should get one. They are AMAZING in what they do for the corals. My corals just didn't get the same growth using the two-part additives. Once I turned on the
Ca reactor things just exploded. It will do the most for
SPS or
LPS but even my zoos have noticed the improvement.
The cons would be more machinary for your system, an added expense, one more thing to tinker with. The
Ca reactor has to be tuned to your system and you're going to have to do it! Nobody can tell you exactly how to set it (though there are great guidelines for how to get it started). It can depress your pH and lots of people tend to need to drip calc into their system along with the
Ca reactor.
The pros far outweigh the cons.
NJRC will be building our own dual chamber
Ca reactors at our February meeting. There's a thread over on RC in the
DIY forum that we're using as our model. Should be a great experience.