I used to use a MiniMed Sport Guard when I was pumping (honestly, I mostly used it before the days of quick-release sets so that I could shower).
http://www.diabetesstore.com/product...lies&bybrand=1
On the MiniMed site, it classifies it as a 500/400 series product, so I am not sure if your pump will fit.
http://www.minimed.ca/SearchResult.aspx?categoryId=96
I then found a Paradigm Activity Guard:
http://www.minimed.ca/SearchResult.aspx?categoryId=35 which may provide what you are looking for, though it didn't specify water-resistance.
I was always quite anxious when around the water, so I can understand your concerns.
It is good that you are thinking about this now and making plans for the event. Good luck!
