[Rovert]

Interesting thoughts.

I'm inclined to think a Ca reactor is the way to go, because of these reasons, but please feel free to comment or correct as you see fit:

1) Space. I have limited room under my tank, and if I'm not mistaken, to make the solutions in a volume that would be sensible for a well stocked 72g bowfront (SPS, LPS, Clams) would necessitate 5 gallon jugs which I just don't have room for. The footprint of a reactor and CO2 tank is smaller than the collective space demands of the jugs, dosing pump and whatnot.

2) Simplicity. Mixing that stuff looks to be a PITA, because you have to replenish far more often than with a reactor which only needs to have new media every 8 months or so. It also requires more storage space for the raw materials.

3) Ease Of Use. I'm told that a reactor, if done properly from the beginning, is a "set it and forget it" scenario. Yes, there are a couple more things to factor, but it seems to be the simpler in the long term in that once set up, I don't have to worry about it for at least a half year, where the 2 part system is something that needs to be replenished twice per month.

4) Stability. Looks like the reactor - again if properly set up - tends to have a more long-term stabilizing influence on tank chemistry, such as pH. You also have the ability to control with greater precision the parameters if you're willing to spend money on the probes and controller to do so.