[air ride newbie]

so i bought a used air ride kit and now i am dealing with leaks all over the place. this is a nitrogen setup and i am going to convert to compressor soon.

first question, does the system rely on the pressure in the tank to maintain height? my bottle is pretty much empty but i have enough to raise the car but it still drops.
even if i close off the regulator to keep air from escaping back into the tank the car will still leak down.

second, if i spray soapy water on the release valves and plug the holes where the air comes out, i get small bubbles. Is this normal?

third, If i raise the car and the inlet valves (not pressure release valves) leak before the valve does that mean the valves are leaking back into the bottle causing the car to drop down?

thanks guys