In my experience, the testing your runoff and estimating your medium pH is at best a wild guess. Sooooo many things that can throw that calculation off a mile. About as accurate as pulling a random number out of a hat. Get a soil probe, preferably an Accurate 8.but doesn't take my caveman brain to figure out that I'll never get better til I learn the basics of this pH deal...so I take my jug test it....up or down it with some drops water ....collect a test off the run off n bam that's my gig???? so ??? if its high or low at that point do I try n fix on next waterin or then.....a shitcakes I'll just read instead of asking for someone to write every little detail just for another noob to ask again tomrow.....its gotta be easy as scrolling on down