I plan to buy a Canon PowerShot G9 for underwater use. I have a Canon EOS 30D, but I do not intend to use it underwater. I would like to seek advice on the choice of housing for the G9. I'm not comfortable with the Canon housing because its depth rating is only 130 ft. (or less?). I would also like to know the pros and cons for the top choices. By the way, if you have negative feedbacks on the G9, please let me know. Thanks.

Dennis