Kushash
Well-Known Member
Good.About a month ago. I will check it again today. It was brand new a month ago and i calibrated out of the box before first use. Havnt had any issues that i know of with it.
I suspect it is off, a month is a long time and hopefully you kept the probe in a solution when not being used.
If it is accurate then we can rule it out. It takes two calibration solutions to get a good reading but one will help if you have one.
Hydroponic PH drops are a good back up to have for comparison.