Jury is still sort of out for me, but thought it might be worth me posting on the topic. I just down graded to two 120 gallon tanks from a 360 gallon that I dosed three part in. I do like three part, but I did have fluctuations, I would forget to fill the alk container when it ran dry for a few days and my alk would plummet, I know this is user error and not an issue with two part itself, but for me it was an issue. I also had a hard time keeping up with the elements, seemed I had to make adjustments to the dosage often, again, could be me and not the method. So when moving to these two new tanks I wanted one LPS tank and one SPS focused tank. I already own the Archon controller and dosing pumps, so that would be what I am using on the LPS tank (still need to set those dosers up, been doing it manually) but for the SPS tank I figured I would take the plunge. I also brew beer so I had an extra CO2 tank around so all I needed was an extra two pH probes, the reactor, feed pump, solenoid valve, regulator and media, okay, that still seems like a lot..... but I have always been curious and based on so many mixed reviews I had to try myself. I am not yet at set it and forget it, but its only been running for about a month. I still tinker with the effluent rate and the bubble count but these are simply turns of two knobs, not mixing salts in water and letting it settle out and setting it back up under the doser and then adjusting the time of each dose daily until dialed in. I simply make subtle adjustments, check the next few days with the Hanna checker, as you do with three part, and that's it. I did have great growth with three part and am not knocking it, but will say it is a little more involved than a reactor.
Three things I like more about the reactor are changes are made much more slowly, there isn't the risk of adding too much Alk solution in a day and coral bleaching from it. I guess in extreme cases this could happen with a reactor but it would take a significant change in chamber pH and effluent rate but with pH probes, solenoid and a controller you can reduce the risk. Also, I cant help but think there is more dissolving into the water than just Alk and Calcium, its everything that made that skeleton a skeleton. And the media is way more cost effective after the initial set up cost, maybe refill it annually and that's it.
I will say my coral has responded well to the reactor and the coralline algae seems more healthy, seems to be growing in thicker layers and deeper purples and pinks. I am still early in the process but set the two tanks up differently so I can get a feel for how they really compare. Hopefully after 6 months to a year I will be able to form a solid opinion, three part works for sure, especially if you address the other elements like potassium, strontium et cetra, but I am pretty optimistically excited about the reactor so far.
