You can use vinegar, ph down or vit C to bring the ph down, play with the well water and see what you can do, pick one plant as a test plant and see what the adjusted water does be careful not to over water. The soil is buffered to maintain ph so it should be OK, a little vit c is good for ailing plants just don't over do it, teaspoon per gallon or so, foliar feeding liquid kelp is also helpful for sick plants and always try it on the tester first and watch the new growth to see if they're getting better.