Periodically I will add a good amount of bleach to the tub filled with hot water and run the jets for a while to clean them out and kill those bad smelly scoobies that are hanging out in the system. Then drain, refill with water and run the jets to rinse out the residual bleach in the lines. Got this tip from one of those home improvement shows and it really does work. (Note: If you're sensitive to bleach fumes, like I am, you may want to open the windows or somehow get some extra ventilation going in there.) I hate scrubbing bathtubs. Ya know that annoying ring that you get sometimes? Anyway, I found that Greased Lightning and Goo-Gone work terrific. Just spray it on, leave it for a minute or so, and you can wipe that ring away with hardly any effort. My tub is cultured marble and these products have not harmed it anyway. Forgot to mention, that we also avoid using a lot of oil type products with the whirlpool.