Yes vinegar is safe to use on acrylic tubs.
You can naturally and safely clean acrylic tubs or just about any other tub or surface using vinegar and some water.
The vinegar is not any harsh chemical as it's natural and even safe to drink some so it makes it very safe for cleaning acrylic tubs, mopping floors etc.
You can clean your acrylic tub by using some vinegar, baking soda and even lemon and then scrub the acrylic tub.
The vinegar, baking soda and lemon all help to clean the acrylic tub without doing any damage to the tub.
I clean my acrylic tub with vinegar and baking soda and it does a great job.