3 different types if ph testers which is correct?

ok im using a cheap soil phtester, a digital phtester, and a phtester where i have to add 4drops of solution to get the ph....and my question is if my digital ph tester is reading one number and the 4drop tester and the soil tester are all reading sumthing different which one do i depend on to be correct????

Confirm the elec. One's are of good calibration, and ditch the soil tester they suck, if yur ph is good going in then the run off u get should be good as well, everything inbetween is also taken care of as well. Db.~tlb!

ok i checked the runoff with the digtal ph tester and it read about 7.8 but the water im using is distilled and reads around 6.8 with the 4drop solution.....o and i dont have an idea on how to calibrate the digital

Check yur instructions if unit is new its prob. Fine... I would go with the dig. And not the drop... Ph's should be at the 6.o mark.

you can purchase a solution which is a known ph, such as 7.01 in my case. when you place the digital meter in the calibration solution, you just have to adjust (usually via a knob or screw slot) the meter until it reads the correct ph. also, if you don't get the storage solution for your digital meter, it will go out of whack on you. you can't let the electrode dry out, or you will have problems.

ph calibration solution can be purchased here: Milwaukee pH 7.01 Buffer Calibration Solution, 3 x 20ml - eBay (item 300210874269 end time Jul-24-08 21:04:01 PDT)

or here: High Tech Garden Supply