Yes! If you can't use lemon juice (aka citric acid) to lower the pH of your shampoo, we recommend replacing it with apple cider vinegar. Make sure to really change the pH drop by drop. Add 1-2 drops of lemon/vinegar, mix well, test and repeat. Because if you go too low in your pH by adding too much acid in one go, there are unfortunately no 'easy fix' to bring the pH up again and you'll have to redo the whole shampoo (chemistry is mysterious in that way).