'less acidic' is correct and usable in written English.
You can use it when comparing two items in terms of acidity, for example: "Lemon juice is more acidic than orange juice, but apple juice is less acidic."
Hydrogen fluoride has solvent properties resembling those of sulfuric acid but is less acidic and has negligible basic properties.
This varies from the high acidity of the stomach to the less acidic intestines to the more acidic colon.
The vagina becomes less acidic, she added.
and is less acidic than Canadian peat.
Very slightly sweeter than "the real thing" but less acidic.
I definitely like that it's less acidic," he said.
The Earth's oceans would be measurably less acidic — and we are, after all, an ocean planet.
It's very much like sangria, only fuller flavored and less acidic.
Fans say the method results in a mellower, less acidic coffee.
For balance, I wanted a touch of orange flavor (tart but less acidic than lemon), contributing a note of fruit.
Without informing the review board, Dr. Togias changed the solution in which the chemical was delivered, making it less acidic.
