very carefully! a little goes a long way.

mix it into a liter af water, a drop or two at a time, a capfull in a half jug of water took ph in the water down from 7 to 5. ive never applied it, but ive practiced mixing incase i need to.

i would guess if you bring the water down to 6 and then watered the plants and re test the soil after a day or two that would be a safe way of doing it.