In Reply to: Re: I think you have a bad valve posted by Cynde on February 20, 2006 at 14:12:14:

I have to get rid of most of the air to sink. Some air must stay in there somewhere because I use an aluminum 80 and staying negative enough to ascend slowly and do a safety stop is never a problem. I can always definitely tell when the tank is getting lighter though.

Sometimes I use the be and sometimes I just wear it. Mostly on deeper dives is when it comes in handy. After attempting "backpack" diving I discovered that putting some air in the bc helps a lot for stability when taking photos. People who dive backpack usually want to be crawling around in the rocks and mud.