I did calibrate and it was at 70 degrees. I thought the meter was reading accurately. It is the same meter you bought Yooper. After your problems I had it in the box for a year. I hope you are right. It was a 50/50 blend with my hard water (similar to your MI water) and distilled water. Who knows, maybe it was user error, wouldn't be the first time.
Having never used acid I thought I had entered something wrong in Bru'n. I went over it several times and I guess the 6 ml was a correct dosage.