Just a note: bleach needs to be dilute to kill mold spores. Straight bleach
will irritate the wall of the spore, it will harden, and not kill the spore.
Spores will allow dilute bleach to enter, and then kill them.
: > What did I do wrong? I removed all of the caulk from around the tub,
: > used a solvent to remove minute traces, and let it dry for three days
: > applying new caulk. I filled the tub with water, recaulked using
: > siliconized mildew resistant caulk and let that cure for a week. I left
: > exhaust fan on the whole 10 days. Three months later, there is black
: > IN the caulk, not on top where I can scrub it off.
: > I don't see any evidence of moisture (loose tiles, or soft spots when I
: > on the walls. This is the third time I have recaulked in 2 years. I
: > thought I had covered every aspect of keeping the area dry and
: > while doing the job. I was told to fill the tub with water because it
: > ever so slightly when full, causing a crack in the caulk that would let
: > moisture in.
: > Any more ideas? I have a white tub, white ceramic tile walls, and a
: > ceramic tile floor. (Whoever thought up this creative color scheme must
: > a glutton for punishment!
: The key word is "resistant." That isn't the same as 'mildew proof."
: blame yourself, it sounds like you did all you could. I would use some
: chlorine bleach on it. It needs to stay wet for about an hour. In
: areas, apply some plastic wrap over the wet area to prevent evaporation
: limit run-off. You will probably be committed to periodic treatments. I
: use Clorox in a spray bottle. You should open a window and/or turn on the
: ventilating fan and close the door in the bathroom. Don't mix other
: household cleaners with the bleach and avoid breathing the fumes. After
: about an hour, rinse the surfaces well with water and dry. If the
: discoloration doesn't go away, repeat. Make sure to use rubber gloves and
: protective eyewear when working with bleach.