Best caulk for acrylic tub

Hi! We are caulking an acrylic tub with a plastic surround (again). We found that silicone doesn't stick very well. Siliconized latex seems to stick well, but the kind we used dried clear, got mold underneath, and looked terrible. Even without the mold, the clear just looked bad because it showed the seams which aren't 100% evenly cut.

Delta's site gives 3 types to use, but I can't find any of them anywhere. Can anyone recommend a white caulk that will stick well to an acrylic tub?