Not many responses... I'll revive the thread with my .02.
I personally couldn't be more happy with adding a CaRx to my 120g system.
With this last 'upgrade', I don't need to pay as close attention. The system runs itself and I don't stress that my alkalinity/calcium has dipped so low to cause an issue.
Still have to occasionally TEST and yes, as media is being consumed, you need to adjust flow rate to accommodate decreased alk affluent, but we're talking finding a TEST being 7.8- 8.0 vs the 8.4/5 that I like to keep it at.
A couple of perks that I think were worth the cost of the CaRx.
1. No more mixing two part
2. No more fine tuning two part dosing
3. No more worrying that a two part dosing pump line is going to spring a leak.
4. No more needing to clean out my ATO reservoir due to using kalkwasser.
5. Reduced calcium build up on my pump heads or sump where kalkwasser used to be dumped.
6. Consistent water parameters
7. Personally, I've cut back on water changes in my SPS dominant tank. The CxRx has kept up. Though that might be because my system has finally reached maturity and my personal experience is you have better 'color' with 'aged' water in the system.