When I switched to a CaRX i was scared I'm not going to lie. Bubble counting, flow rates and co2 all scared me. But after I learned that you can use this effective means of "dosing" easier I was sold.
First, get a good reactor. I recommend the appropriate sized Geo's Reef reactor. Second, good media. I use TLF Reborn media that won't leach phosphates and is very clean right out of the bag. It only took me 2 minutes to rinse it before putting it in my reactors. Third, get a regulator that has a good solenoid. While the carbon dosers are nice I don't feel it's totally necessary the way I run my reactor. Fourth, make sure you have a controller lol. And last, just get a decent feed pump. Peristaltic pumps are nice but pricy and aren't really needed IMO if you run your setup this certain way.
Forbthe ph drop concerns add a 2nd chamber. I was having low ph when I just ran the CaRX alone. My ph was regularly between 7.9-8.1. After I added the 2nd chamber my ph has been back to its "normal" 8.1-8.4 range. So that's an easy "fix".
Now for the fun part, how to run the system. This version is easy, you adjust the ph in the reactor not the bubble count or effluent. You want the flow out of the effluent to be a slow, steady flow. A little faster than when you can see the tiny bubble formations be almost uniformed. You start the ph in the reactor around 7.08as your low setting and then your high would be 7.18. You then test your alk to see if it dropped, if it did then lower the ph by .01 on your controller to turn your regulator on and off. Here is the video I used to set up initially.
And here is a quick walkthru video of my setup
I also know some ppl have issues with magnesium being low, but you can add the appropriate amount of magnesium to the reactor as well to help with this. I've never had an issue with it since I use salts that have higher amounts of mag already so it barely moves at all weekly
