I've had that problem in two-part showers. Often, the mold was under the caulk, where no cleaner will get to it. Get a good quality, mildew resistant caulk. Pull out the old caulk, clean thoroughly with bleach or other mildew remover. Let dry - bone dry. Replace the caulk according to instructions.
In my experience this has to be done every 4 - 5 years. It isn't hard, just a PITA.
|