Had a close call yesterday with Ca dosing

[Reef Pilot]

I adjust my Ca dosing once in a while with my Apex. I dose Ca during the day, and Alk at night. So yesterday, wanted to add an hour to my dosing, changing the stop time from 12 noon to 1 pm. I changed the Apex Outlet coding from 12 to 01 (for 1 PM).

Well, about 9 PM last evening, was looking at my sump, and noticed a drip happening from the Ca dosing tube, and the Ca doser is running. WTF, I thought!! Then I remembered that my Apex time is referenced by the 24 hour clock, and I should have set the end time to 13. Dummy me...., I change this setting about once or twice a month, and this time I still forgot about the 24 hour time clock!!

My fear then was that I over dosed my tank with Ca. The doser ran for 10 hours vs 2 hours normally. So I tested Ca, and to my surprise it was only at 420. And it was at 400 that same morning, before I changed the Apex. I also tested my Alk, and it stayed the same, at 8. So that was a surprise. I expected my Ca to be way up, and possibly my Alk to have dropped. I checked it again this morning, and it is still the same.

So looks like nothing bad happened. Does my tank, with all the live rock and corals, have a large buffering capacity, which prevented a larger swing in these parameters?

I think I will also change my Apex start/end times to be in the afternoon, so I don't make this mistake again.