The 2 part route just seems easier to me. X amount of this raises Z this much... no guessing and no crazy swings. The dose just does its thing independent of the ATO or anything else. You DO need a doser you can trust though. I went through some dosers here that now sit on a shelf. I did some testing on the Kamoer X1 Pros and the new Red Sea dosers and both are accurate to the drop and hold calibration very well.I saw a thread with some issues also, though I didn’t understand how it could be Happening from a chemistry perspective. I am targeting about 8.5 dkh. I am doing the math on AFR+Kalk to estimste how much alk I’m adding and monitoring my consumption periodically with daily tests and adjusting. It has been fairly predictable except a problem I was having with my float switches.
My top off plus the kalk was causing the water level to hit my high level float. The result was shutting down kalk, AFR, and top off until water evaporated below that level. This means I had days where I was not dosing the targeted amount making my Alk swing low. I didn’t realize this so I bumped up AFR making the Alk swing high. Even then the swings were 8.2-8.85. Not good enough but not a disaster.
I have adjusted my top off program so it doesn’t fight the kalk addition. I am still hopeful I can dial it in. Will report back. If I cannot I will switch to 2 part, which is the longer term plan anyway, just starting with the supplements I already have.