I've been using Ca reactors for close to 20 years. If you can make it fit in the budget a calcium reactor is the only way to go. Your basically recycling coral. All the properties and elements are present in the media usually in the right balanced concentration which dosing lacks. For High consumption aquariums in the long term they are very cheap and less headache than dosing. Just do it right though or you may be sorry.
A) I would not recommend them if the reaction chambers ph is not being monitored and I strongly recommend the co2 solenoid to be controlled by that monitor. ( if the ph in the reactor is above 6.7 it's barely dissolving anything. ) I run mine at a pH of 6.2-6.3
B) I would suggest also a fail safe to shut off the CO2 solenoid if the tanks pH drops below 8.1
C) I would strongly suggest a properly sized secondary chamber full of aragonite post reactor to elevate the ph back up. Commonly called a effluent chamber.
D) Use a reverse flow reactor to prevent channeling or clogging. (The water flows upward in the chamber)
E) Use quality media (they are only as good as what they are dissolving) and regulator, there are some garbage regulators, and reactors for that matter.
F) I'd still recommend testing all the levels weekly even after the reactor is dialed in. As the coral grow or more coral is added the consumption rates change and the output of the reactor needs to also mirror those changes. Also occasionally Alk, Ca, or Mg only supplementation may be necessary based on test results.
Can't beat them or the long term cost savings if done right. It's hard to argue or beat their effectiveness if they are understood.
