Hasn't really been a recent thread on pH meters so I'll just start a new one.
My last pH meter broke over a year ago and I brewed without it for a while. Just recently purchased another Milwaukee ph55.
When I went to calibrate the new meter I figured I'd just use the solutions I had on hand which were bottled solutions from probaby two years ago. The meter liked the 7.0 solution but when I moved it to the 4.0 in the second step of calibration it kept failing.
So I opened the little packets of solutions they sent me and calibrated the meter. Then read the old bottled solutions to see what I got. The 7/0 read 7.1 but the 4.0 solution read 5.1 confirming my past suspicions that there's a limited shelf life on the solutions.
Anyone have experience with solutions that last longer or should I just buy a few of the little packets to keep around. The bottles are pretty expensive if they're not going to last.