I am currently setting up to start a grow and from what I understand the Ph run off should be around 6.0 to 7.0. I did a test using
Fox Farm Ocean Forest and when I tested the run off it was under 6.0. I read some info saying to add 5 to 6 tablespoons of dolomite lime. I added it mixed it in with the soil and got the same results. I am using 4 gallon pots and am curious about how much dolomite lime I should use. I don't want to over do it because I added a lot more and it actually changed the soil whereby it seems hard like mud when wet and this happened when I decided to try the pelletized dolomite lime.
Why are you concerned with run-off here? Are you having problems? If so, what are they? You're chasing numbers and you'll kill doing that. Observe, THEN make changes if observations say they're warranted. If you haven't even started then you're not even correctly testing the soil itself using a method like this.
After that, don't mess around using a pH run-off method, especially for organic soil. Use the slurry method.
What you really want is for the SOIL to be in the pH range of 6.2-6.8. HOWEVER, there's a caveat--you're doing organic *and* soil here. So if you're planning on futzing with pH, you're probably not going to be doing a very organic grow, or if you're planning on doing organic you're going at it very, very backwards.
Get the book Teaming With Microbes, read it, learn what the soil food web is and understand it. Then get yourself some organic gardening books, Eliot Coleman's information is FANTASTIC. Learn what aerated compost teas are (they'll be discussed a bit in the TWM book), use them.