I'm with Dave L on this one, I know you said you took the 'brightness' right down but what shutter speed did you use? I have a sneaky feeling that you had your camera on a slow shutter speed.
Best filter to use for Jupiter is an IR pass filter. It blocks RGB which means that you dont get the colour fringing that youre talking about. Just make sure you have the cam in b/w mode. Now you'll only get a b/w image but it will contain much more detail.
The most critical thing about jup being so low is frames per second. This effectivly controls your exposure. eg 5 fps is 1/5 sec 10 fps is 1/10. the faster the exp the better chance of capturing a bit of steady seeing.
  