Re: Continuously mold tub caulk
What was the original caulk that you removed?
Silicone is some NASTY stuff! When it fails, and it does more frequently than not, it's nearly impossible to remove sufficiently enough that even more silicone will stick, let alone acrylic/latex caulk.
Also, removing old moldy caulk, it is likely that there is moisture behind the finished wall surface that doesn't dry or migrate out any too quickly. You could have a mold problem, there's no way to tell without removing the wall surface for inspection. In lieu of that, spraying the joint with a heavy bleach solution will go a long way to killing the mold. Leave the joint open with a fan for air circulation for at least a week. After that, recaulk with a good brand of tub and tile caulk. Sometimes in extreme cases use a mildew resistant caulk.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!