One of the following five (5) things have occured;

a.) After cleaning with Step I, the surface was not rinsed well enough, leaving behind acidic salts that were reactivated by Step II. This causes microblistering, and subsequent peeling.

b.) The surface was not cleaned and some body oils, soapscum or silicone oils were left behind causing the product not to bond.

c.) Not enough time was allowed between coats thus allowing moisture trapping.

d.) Too many coats of Step II & III were applied and excess product is coming off.

e.) Steps II & III were applied to areas of hard gloss on the tub.

Correction
Remove Steps II & III with ammonia and a Scotch-Brite pad. Reclean surface thoroughly, rinse with plenty of warm water. Any areas of high gloss left on original surface must be sanded dull with 320 grit wet sandpaper. Place 2 coats of Step II allowing 7-10 minutes between coats: if using a fan 30-45 minutes if air-drying only. Place 3 coats of Step III, following above guidelines.