Our tub decals are only about a month new, and are already starting to peel off. Is there something I can do about this?
Normally I wouldn't advocate against using a lifehack, but be wary of using anything that would make these decals truly permanent. While there are definitely ways to keep these from coming up, they might work so well that if you went to sell your house/get your security deposit back on your apartment you could get stuck paying for a new bath tub if there is residue left behind.
...Perhaps you would better off financially in the long run simply buying higher quality tub decals...
Source: I own and am renovating fixer upper, and permanent bathroom decorations knocked 5 figures off the house price.
Use silicon based caulk when the tub is dry to glue the decals back on. Or any tub-caulk in fact. Home depot or Lowes or local hardware. Get a small tube.