m0useanswered grow question 2 years ago Any acid can work, but some are more stable or longer lasting in the medium. ACV is raw and if it has the mother it's an added benefit of giving some Lacto bacteria to the soil.
Vinegar is also a week disinfectant and can harm soil microbe life.
Other options for PH down are phosphoric acid, Nitric acid, citric acid, hydrochloric acid, sulphuric acid,
I'm more a fan of the first one and some organic growers like citric and or vinegar. The last two are a bit aggressive and can cause more problems then solve.
Good Luck!