Phillip, what type of caulk are you using? And alcohol...Denatured, right? (not scotch, I hope, lol-kidding) Is this a porcelain tub, or fiberglass? And the walls, tile and grout? All I can think of if it's being cleaned good would be it's not adhering to tile grout because the grout hasn't been allowed to thoroughly dry out before reapplying, and built up soaps and moisture in the grout are working against you, or the new caulking isn't being given enough time to cure before getting wet. Can you give us a bit more info?