Originally Posted by gamer565
If it's not leaking when it's not on the marker, then chances are it's not the tank...
Sounds like your marker is leaking.
Agreed. Take your tank off the marker (hopefully you still have some air left in it) and dunk the reg in a glass of water. If you see any bubbles, that's your leak. No bubbles means the leak is in the marker. Sometimes you can't hear a leak, but the bubbles never lie.