Lance's 225 gal tank

[Lance]

What the #%&* is going on?

I dose 250ml of BRS Calcium Chloride every morning via dosing pump (which takes 2.75 hours); and 230ml of Soda Ash via dosing pump in the evening (which takes about 2.5 hours). I manually dose 100ml of Mg every third day.
This regimen keeps Ca steady at 420 to 430; Alk at 8 to 9 and Mg at 1300 to 1325. I test every 2 weeks and these numbers never change.

UNTIL TODAY! Ca = 520 Alk = 5dKH Mg = 1320
I immediately thought the doser dripping the calcium had gone wonky and was over dosing which would also drive the alkalinity down. I checked the doser and it measured out exactly 250 ml. So I checked the alk doser as well and it is working perfectly. WTF!

I remember I opened a new container of BRS calcium chloride a while ago. Is it possible that BRS's mix is off? Or the wrong label was put on the pail? Anybody run into this before? I don't know whether I should throw the pail out or keep using it and adjust the dosing volumes. Thoughts?