Can you give me advice on how to remove the bathtub mildew in the caulking? Is their a product that will keep it under control? Or do I need to remove it completely and start over again? We have at least 4 showers going on a day so it is constantly moist in there. Thanks for your help.
Mildew typically grows into caulk and therefore can not be easily removed. The best offense is a good defense. I'd suggest removing the old caulk and replacing it with a bathtub caulk that includes a mold/mildew inhibitor. DAP makes a product called Kwik Seal Plus  that has a inhibitor called Microban which has shown success.
And since you are going to have to replace your caulk anyway, here is a tip to make sure it stays put, fill the tub with water before caulking. The weight of the water will force the tub to sag a bit. Then, after the caulk dries, drain the tub. This compresses the caulk so it won't fall out and mildew in your bath will no longer be a problem!.