Yesterday, I replaced the caulk in one of my bathtubs. I thoroughly removed the old caulk and cleaned the surface well. I had a unopened tube of DAP Kwik Seal kitchen and bath adhesive caulk, so I used it. However, it does not seem to have any silicone rubber in it because it is not flexible when dry. This is what I want. Should I remove all the caulk I just applied or can I go over it with a silicone rubber version? There is plenty of space for another layer of caulk as I wanted it thicker anyway. Thanks in advance.

Dap Kwik seal is perfect for this application. Unless you have a defective tube of caulk you should be just fine. Any chance of a picture? I am concerned with your description, if you already caulked there should not be room for more caulk. Either the gap is too big or your first caulk job was too sparse.

I would never caulk over existing caulk. Ballenger is right, unless the caulk is defective you may have misjudged the amount of caulk you needed. A couple of years ago I made the beginner's mistake of grouting against the tub. Well, that didn't last too long. So I had to remove the grout and that left a nice size gap to caulk... and I needed A LOT of caulk.

If you actually do need more caulk I would pull out what's already there. Then use blue painter's tape to set the boundaries of the caulk. Add caulk and smooth with a damp finger. You may need to do this twice if you needed a lot of caulk. Then remove the tape and go over the caulk one more time with a damp finger.

Use 100% silicone... mold and mildew resistant. It will say this right on the product. Caulk will not hold up and will turn black over time.