The 10 lbs. of dichlor should have added about 15ppm of CYA and the 12 lbs. of CYA should have added about 40ppm. So, a total of about 55ppm.

I'm not sure how the extreme cold would affect the testing reagent. Maybe Ben knows. As far as the CYA itself being bad, I doubt it. I often keep it from one year to the next and have never had an issue.

At any rate, for now, I'd assume that I had 55ppm of CYA in the water. When it has been a full week since your last addition of CYA, test it one more time and see if you get a different reading and let us know.

Let's see what Ben's thoughts are about this. He should be back around sometime this afternoon or evening.

Congrats on the new pool!