Lemon juice, Apple cider vinegar, to Ph up, and Baking soda or Dolomite can be used to Ph down.
You just gave him the exact opposite of true and accurate information. Lemon juice, apple cider vinegar, and all acidic liquids will lower your PH. A low PH is "acidic", makes sense. Baking soda, or dolomite lime, is alkaline, and is used to raise PH. You'd be best using
lemon juice to lower your PH and
baking soda to raise it. The organic AN PH down is just citric acid, and organic AN PH up is sodium bicarbonate, more commonly known as baking soda. Buy whichever is cheaper, just watch using too much baking soda to raise PH, if that is ever an issue, or you could lock out some nutes.