Robert Phillips:Catalina Scuba Luv is just up the street from the green pier and you should get a coupon for a free air fill with the packet you will get in the mail shortly before the event. If you are bringing a tank, your best bet is to have it filled before you make the trip over and use that for the dive.
The cleanup is a one dive deal. You do not get multiple dives during the event. Once you are out of the water you are done in the harbor. But you can still head to the point or to Scuba Luv to get your tank filled and dive the point after the event.
If it makes you feel any better, I'll point out any trash I see on the Yukon that day