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Is it the blue tooth system or the JBL one?
If the stereo is the black blue tooth one there is a btn inside the box. From the control pad I believe you can just hit the music icon then hit one of the other btns to exit out of the radio. Sorry I don't have one hooked up right now I sold it last week. And I don't have a manule here right now..
Three ways on my Jacuzzi w. the J1000 controls. For 2012 model, look at then radio system on the front left hand side. Right above where the door opens to insert the iPod, in the center is a small square button that has the JBL symbol. Push it to turn on and off. Second, on the LCD on top of the jacuzzi where you turn on and off the jets and programs, on the home screen, hit the upper left button and click twice to turn off or something like that (I don't have it in front of me). You could always use the remote as well.
After reading pages 45 though 52 or so, I don't see where you can turn it off with the keypad? Unless I am missing something, I can call Jacuzzi in the AM and find out, but I sure don't see it in the manual. Only place I know is the btn inside the unit, upper center.
http://www.jacuzzihottubs.com/brochures/J400_English_Web.pdfOn mine, from the audio main screen, hit button A twice to turn it off. Additionally, if you want to access the diagnosis screen to check errors or adjust then amp rating from 50 to 60, do the following on the quad key pad: left arrow 4 times, right arrow 4 times and then the center button. Be warned, be careful with any settings you adjust in this mode. It's better to look but not reset anything.