The person who started this thread was probably looking to use a standard co2 regulator and adapt a paintball tank for use with it. That's why there have been mentions of the on/off valve. You would only really need the valve if you wanted to screw on a regulator with CGA 320 threading. The sweet thing about adapting the tank, rather than buying a paintball-geared regulator is that it'll be extremely easy to switch from a paintball tank to a regular tank if I decide to do that later on. I think there are ways to adapt the paintball-geared regulators to the bigger tanks too though
The pressure of your tank should be variable with the temperature, so if you keep it warm in your place in Delaware, that would explain it. My dorm room is kept at a temperature of 73. As for any leaks, no there are none in my set-up. So far at about 1-2 bps, the paintball tank has been going for 2 months now.