welcome to SPS-level consumption fed by halides
Wait til you have more of them.
if it's any consolation, I add at least 1-2 hand fulls of Ca, 1-2 handfuls of Magflake and 1 handfuls of baked baking soda to my week's worth of topoff water. One of these weeks I'll check my levels and make sure they're OK.
The simple fact is, if my xenia pulses in my tank, the alk is on, and if my birdsnest look happy, my Mg is on, and when my acro and caps put out new growth, I know Ca is about right. The other 'sensor' is coralline growth.
Also, If the growth of HA in the overflow, and cheato in the refugium isn't bad, I know phosphates are in check.
The only thing I do watch is pH by sensor, salinity 1x a week or so, and nitrates right before a water change to see if I need to make it any bigger. Even after totally tearing down my 72 3 weeks ago, and moving it 8 feet to do the kitchen floors, I never saw detectable nitrates.
All in all, my hands-off lazy, keep-your-hands-out-of-the-tank husbandry has led me to the most success with my tanks......