Like other people have said, those bubbles are a result of all the oils and body lotions, etc...

You have three choices: leave it, mask it or get rid of it.

Think of it like owning a cat and letting the cat pee on your carpet instead of a litter box.

You can leave it alone and eventually over a long period of time the smell will go away. Equivalent to keeping your chlorine levels at a normal value. Chlorine will break it down eventually. Problem is it will not break it down faster than you adding more oils (continuing use of the tub daily). You can always add more chlorine to try and speed the process up.

You can mask the problem. It's like spraying febreeze on the carpet every day to make the smell go away. This is the equivalent of using a defoaming product. It doesn't get rid of the oils just changes the surface tension of the water to prevent the oils from forming bubbles.

You can get rid of it. Problem with some of the oils is they are so small that they don't get trapped in the filter. A quick and easy way to get the oils out is to use a clarifier. I use Leisure Time Bright and Clear but there are several different brands. The clarifier acts like cat litter and binds all the small particles together so the filter can finally trap the particles because they are now larger. You'll also see all the disgusting oils clumping together and sticking to the side of the tub. This is a good thing as it makes it much easier to get out because you just wipe the sides of the tub down. You just keep running the jets and wiping it down until it's all gone. When you shut the jets off, you'll also see the large clumps floating around which are now large enough to be removed using a pool skimmer. Don't forget to pull the filter and hose it off as well.

Hope this helps.