I just got an scba hose adapter from Joe Brancato and he is a great person to deal with. The first thing you need to do is to find out from Sport Chalet exactly what fitting they use to fill from. Second, call Joe Brancato and tell him exactly what Sport Chalet said they had. Then, voila, Joe will come up with what you need. It may cost some, but the adapter I got from him is topnotch and I never expect to have any problem with it!
Blessings, Joe