Epsom Salts are not sodium chloride (table salt) it is a mineral magnesium sulfate. Also the pH of Epsom Salts is neutral and has no effect on soil pH. To learn more about Epsom Salts go to: www.epsomsaltcouncil.org
There is a section for gardening.
Testing your soil is always a good thing. We have high alkaline soil in Calgary. But it is the water that changes things for gardening. In July, the water can have a pH as high as 8.3 or more. Rain water is best for the plants and amending the soil helps too.