What should i be using to caulk around the tub where the tile meets? Silicone or latex? I heard that the two do not mix? If I ready have one type I should not apply a different type touching it?
You need to use a kitchen and bath caulk with microban. Any home center will carry this product for you. Silicon is what it should be.
Mixing the two does no harm, but I doubt you have a latex caulk in the tub. Most latex caulks are used for lumber and painting projects.
The reason that they do not mix is that latex dries hard and does not flex, while silicon stays rubbery and can flex and move with the wall vibrations. The adhesion if the two were used together will fail between them.