Back to town :D

[gregzz4]

My hand held pH meter is very disappointing
I calibrate it and use it once ... it's fine
I store it in RO water and the next time I use it it's already off by .5

I follow the instructions on mine and all is good
Using your 4.0 and 7.0 cal solution @ any room temperature is OK between 75 and 85
I rinse my hand-held very well with RO water between solutions and it's always been good to go
But, as I said, it doesn't always last long