The directions for any tub are for you to shower first prior to entering. I understand that none of my customers really adhere to that. However, lotions and the like will indeed cause issues as wmcall noted.
If you absolutely must enter the water with that on your body (and I do not recommend that as its tough to remove oils) use a product specifically designed to remove said lotions and oils. In addition, purchase a "Scum Ball" or buy a fresh sleeve of tennis balls to put in the tub to help pick up the contaminants.
Hope this helps. Good luck moving forward.