yeah we got the same meter. in the instructions it only says to use a freshly decanted solution of 6.89 or 4.01 to calibrate. i let my solutions sit for a few hours to decant then slowly poured some solution to calibrate. but i always get 5.4-5.5 with the 6.89 solution. dont know if the 2 hour style will work with this type of meter since it locks on to the PH level when done. no adjustment screw or anything i could find. guess im stuck on this for a bit til i can get it calibrated correctly.

stay irie