Not sure if you are still looking for an answer but they need to be cleaned out regularly. I have one and they said when it was fitted it should be cleaned around once a month, depending on how often you use the jets.
You can buy a product from Jacuzzi called J-MX 07 which is a broad spectrum disinfectant and degreaser. You just fill the bath above the jet level and add one capful. Switch the jacuzzi on and let it run for one minute and then drain (or, if you're cynical as I am, let the solution sit in the pipes for a while and run the jets again) the bath. They say there's no need to rinse the pipes though but I always do.
If you are going to use the jets, it is very important that the pipes are kept clean. If it's very noisy, check whether or not it is sitting in a balanced position and that the motor is touching the bath or anything else (which is what happened when mine was first fitted).
I was going to put the link to the Jacuzzi website but the page won't load, just type in Jacuzzi UK and you'll find the product there or visit a shop that sells them. Liquids for a spa bath won't work as they operate on an air based system.