What do you use? Calcium Reactor
How long have you been using that method? about 1 year
What do you like or not like about it? Stability, and it's not really set it and forget it....but it sort of is?
Cheapest supplement or media you have found? I have only had to fill the chamber once, and still have plenty left.
Do you have any plans of switching? Nope, CaRx feels like a winner to me.
Previously I tried Kalkwasser dripped via ATO, I had a brain fart and mixed a fresh batch of Kalk and then did a water change (as I siphoned water out the ATO kicked on and flooded sump with pure Kalk....which I didn't notice) end result was a nuked tank. I would never run Kalk through and ATO again.
After that I went to the BRS 2 part with magnesium, using BRS dosers. I like their supplements, and I thought their dosers worked just fine. Probably for a variety of reasons, my tank never took off with it, I never dialed in the correct dosage and was also bothered that I dosed more of 1 element than the other....I don't think it is supposed to work that way. Eventually I switched to a Dos via Apex, this was even nicer but again I never had a great success. I used 3 part dosing for about 4 years.
Now I'm using the Calcium Reactor. I feel like it has a big learning curve, and I only have about a 30% grasp on it. But it is dialed in, and I am starting to see consistent test results and some actual SPS coral growth. I'm happy, going to continue to let it run for the foreseeable future.