Unsanded caulk has a smooth appearance and texture.
Marble trim seal or caulk first.
Use sanded caulk any time you use sanded grout and in joints 1 8 inch or wider.
I used this sealer and just put it in a spray bottle and sprayed three coats on the ungrouted tile.
Magic tub and wall peel and caulk strip create a tight seal between the bathtub and wall to keep moisture out 7 8 inch by 11 feet white 3 0 out of 5 stars 345 caulk tape self adhesive sealing caulk strip waterproof repair strip for bathtub kitchen sink basin edge shower toilet and wall mildew sealing tape 1 5inch width x 10 5feet length.
Caulk comparison dap lexel ge sashco kwik seal loctite ge ii red devil ge supreme dow corning quantity oz 10 10 5 00 2 80 10 50 5 50 5 50 10 10 10 10 10 10 10.
Starting with the first question here.
At the first instance the new caulk will stick to the moldy caulk but after drying out newly applied portion will come out of the surface quite easily.
Doing so will give the mold opportunity to extend further and break the bonding of the older from new caulk.
Because marble is a natural stone and will absorb color you need to seal them before you grout to prevent the grout from discoloring the tile.
Then i used a grouting sponge to wipe off any excess.
Caulk can be either sanded or unsanded.
It has a grainy texture and appearance.
Hold the caulk gun at a 45 degree angle and do a few practice runs on a piece of paper first to get a feel for how much pressure to apply.