Warning

Posted by Unknown on 27th Sep 2012

This product is almost impossible to calibrate.
It has a tiny hole on the back where you insert a tiny screwdriver (not supplied). In order to see the slot on the screw you must hold a flash light in one hand, the meter in your second hand, and the screwdriver in your third hand. It requires a turn of about one hundreth of and inch to move it from a reading of 7.5 ph to about 5.5 ph. After about half an hour of going back and forth, I think I got it to about 6.5 ph. It also requires an expensive calibration solution which you throw out after each use.
Each time I put it in the solution to see if it was calibrated properly it gave a different reading. Save your money.