Step-by-step instructions of HOW TO SANITIZE YOUR JETTED TUB:
1) Clean the tub with a household bathroom cleanser. Before sanitizing the
tub, it should be as clean as possible to ensure the effectiveness of the
sanitizing process. Scrub the jetted tub with a product like Soft Scrub or
Clorox Disinfectant (nothing abrasive) to wash away any dirt, grime or mildew...
3) Pour a cup of bleach or white vinegar into the warm water and turn on the jets and allow them to run for at least 10 minutes. While bleach is fairly inexpensive and works best, you might also opt to use a special jetted tub cleanser. The benefit of using these products instead of bleach is that they are formulated to sanitize the jetted tub without the harsh properties of bleach.
4) Turn off the jets and allow the solution to set for about an hour to loosen debris on the pipe interior walls.
5) Run again for about 10 minutes, drain the jetted tub.
6) Fill the tub a second time and add a few tablespoons of automatic dishwasher powder (Cascade), run for about 10 minutes and drain. This is important because bleach is dangerous if it is ingested or has sustained contact with skin and to ensure that you've gotten all of the bleach out of the tub and the jet lines. The warm soapy water will wash away any existing residue and leave your jetted tub sanitized and looking and smelling clean.