Gene, Dennis,
The best range for pH seems to be between 6.5 and 7.5, it is difficult to achieve an actual exact pH.
I measured the pH of Dolemite Limestone, Potting Mix, Garden Soil and Water last year only because another Forum member had asked, but I usually don't measure, I just add Dolemite Limestone to my potting mix at 1 cup per 5 gallon of mix to start, with an additional 1/2 cup of limestone per month for the first two months. For the Garden, in the spring I add limestone per the "Mittlieder Method of Gardening Pre-plant" at approximately 4 cups for every 50 Square feet.
Dolemite Limestone Granular, Pulverized and Pelletized doesn't change the pH values as radically as most assume. The measured pH of 2 tablespoons of pulverized limestone in 4 oz of stirred distilled water with a pH of 6.7 is pH of 8.9. Many farmers use Agricultural Lime, Quick Lime and Hydrated Lime which are processed lime products and are much more alkaline and caustic.
Ulster County, NY Zone 6a/5b
Garden Soil had an average measured pH of 6.4
Water had a measured pH of 6.8 to 7.1
Potting Mix (5-1-1-1) had a measured average pH of 6.7 (at the end of the growing season when they were measured).
The measurements were taken with a Fisher Scientific Accumet pH meter, and was done by a Certified Lab Technician whose services were paid for with figs and a promise for more in 2014.
<Edit> Other cultural practices that help to maintain a stable pH are cover crops, application of compost, green manure and Espoma fertilizers with Mycorrhizae microbes on the garden soil in the Spring. The Espoma Tone are added to the initial potting mix and monthly as fertilizer and for establishing healthy microbe colonies in the containers.