Hey GC, got a question here about my Hanna pH meter. I have calibrating solution that is 4.01 and 7.01 to calibrate the range. My technique is this...I put my meter in 7 and calibrate, rinse and dry, calibrate in 4, rinse and dry, then test my water. When I put it in 4 to calibrate, rinse and dry and test, my readings come up in the 5 range. When I put it in 7 to calibrate, rinse and dry and test, my readings come up from 6.8-7.3 range. Am I doing something wrong in my technique to get accurate readings? If so, what would be the correction to my possible errors? I need to do a flushing and need to make sure that my R/O water is correctly pH'd. Thanks.
You want to calibrate it for what you're looking for. Cal to 7 and leave it be, unless you're expecting some acid, then cal it to 4. If you want to go back and forth all day, at least start with the 4. I use those things for work ALL THE TIME and people over kill them here. Cal it only when you think it's off, and store it with just a damp paper towel in the lid and it will last you years.