Jetted bath tubs have unique problems with collecting dirt and grime around the jets. These jets, because they are moist, are a prime growth area for mildew and crud. Because the jets are often ball-shaped with small internal holes, they are often difficult to clean using regular cleaning techniques. Fortunately, many jetted tub manufacturers recommend homeowners use a common household product like liquid Cascade Complete and bleach in their jetting system to help clean and maintain the internal jetting system and their jets.
Fill the bathtub with 140 degree Fahrenheit water until the water is at least 1 inch above the jets.
Add 4 tbsp. liquid Cascade Complete to the water. Add 1/2 cup of household bleach to the water.
Turn on the whirlpool jets. Allow the jets to run for 10 to 15 minutes. Turn the jets off. Empty the tub. As the tub is draining, use the old toothbrush on each jet to scrub off any grime that is still clinging.
Fill the tub with cold water to cover the jets. Run the tub until dirt and debris stop coming out of the jets. Drain, and repeat. If more crud comes out, consider running the cleanser cycle again, particularly if this is the first time you've cleaned the tub this way. You may have a lot of build-up inside the tub pipes.