Great advice with cross checking with PH drops or strips. With my BlueLab PH meter I calibrate it at least once a week, and leave it overnight in probe solution every couple weeks. That way it stays pretty accurate. With the BlueLab EC meter I clean it once in a while with a slightly acidic solution I make from water and PH down.
Actually I’m doin the same by ph drop .
But the bluelab need once a month calibrating and also i have prob sulotion and never let my ph prob dry .
I always use RO water as first and end of checking ec and ph prob with.
But avidic solution for Cleaning Ec prob is looking new to me
I just clean it easily by clean towel and put ph and ec prob in the box for don’t take any dust or light as well .
I think my concern is scale now