The Kelway Soil pHD can more than pay for itself the first time it is used. The instructions include guidance on how to adjust soil pH. To test soil acidity the tester is inserted 2 inches into moist soil, and in minutes - the pH is displayed on the meter.
If soil pH is right - leave it alone. If soil pH is wrong - you should add limestone to increase it or sulfur to lower it. Until you correct soil pH, you are wasting time - energy - money because fertilizers can't dissolve in very acid or very alkaline soil and can be almost useless. Fertilizers will dissolve when you water them into soil at the proper pH and this is the only way your trees, plants, flowers, fruits, vegetables, and lawns can be fed. The same is true for the normal bacteria which live in the soil and promote soil enrichment. They function best in neutral or slightly acid soil.
The Soil pHD creates its own power, really, infinitely tiny current between the tester's two different metal rings. No batteries needed - ever.