Jyetman
Active member
So my PM2 module was repaired and when I plugged it back in my COND was reading higher. I know it was off today when I pulled the probe out of the water and it was reading 3.5 instead of zero. So I decided to go ahead and calibrate it with pinpoint 5300 solution. The bottle was from last November and half empty wrapped tight in a baggy stored in a sealed container. Short story it doesn't calibrate to specs. Tested the solution with a Milwaukee ma887 says 37 PPT should be 35 PPT. After many attempts I said a few curse words and made my own solution since I know what my tank parameters are suppose to be. During the calibration phase I added drops of fresh RO water to the solution until the apex read 35 PPT. The tank water now reads where I want it 34 PPT. Does the calibration fluid go bad even if stored in sealed bottles? If I remember correctly last year when I calibrated it was extremely difficult must have fudged it then too.
