Advice? Ca Reactor

For the most part, yes. However, you can still experience some drift away from balanced Ca/Alk/Mg parameters. Odds are your tank's uptake won't be perfectly in line with the crushed coral and mag supplements in the reactor. If I remember correctly from when I was running a Ca Rx on my SPS tank, the Ca Rx generally resulted in a downward drift on Ca if I managed to get Alk dialed in perfectly. The Kalk stirrer was the opposite so I ran both to try to keep parameters balanced. Eventually I got frustrated with constantly tweaking these and never getting it right long term so I went with 3 part dosing.