First you need to know what your calibration points are- some meters are single point, better use all three.

If you're only going to be working w/ solutions in the 5-7.5 range, you only need the 4 and the 7. Doesn't matter if the meter's accurate @ 10+, cause you'll never go there.
rhizome Reviewed by rhizome on . Ph buffer solution preferance After waiting 3 weeks I just received my ph tester but they didn't ship me any buffer solution and since I'm new to this I didn't even know you needed it. My question is which buffer solution is best. My tester states there are 3 kinds, #4, #7 and #10 which I have no idea what the difference is. I have to order this so I'm hoping someone can give me their input on what is best. Rating: 5