chop,
Scott's offer could be the best way to go.
But I'll try to explain the workings of your 2nd stage regulator a little bit, so you have a better understanding and you might want to give your LDS one more stab at it first.
It's not uncommon for a new 2nd stage to have a hissing leak after just a few dives. Regulators are set for very good breathing performance at the factory and checked for leaks. Sometimes it takes a few dives for the seat in the second stage to take a set, and then it developes a slight hissing leak. Tightening up the 2nd stage means adjusting the breathing resistance control (the knob on the far right in the diagram) in a clockwise direction until the hissing stops. This should not take very much rotation, maybe just half a turn, or so. You are compressing the spring seen in the cutaway and putting slightly more pressure on the seat which should stop the hissing without undue loss of breathing performance. If it does it again it would be prudent to try another half turn.
A regulator that has the adjustment tightened all the way, or nearly all the way clockwise, will not breathe easy like it should. The regulator should be taken in for service to return it to proper easy breathing performance without leaking.
If it keeps leaking after several attemps to adjust out the leak, it is showing there is another problem.
Likely problems might be: (Note that only a regulator repair tech normally would correct these problems.)
The seat may be scored or groved. Usually this occurs when it gets older and hardens, but not always.
The seat may have debris on it that prohibits a good seal.
An unlikely problem might be that the regulators 1st stage is overpressuring the 2nd stage. It is prudent to check the IP, intermediate pressure, to be sure it is proper and stable.
About one thing you said, ("not sure what this entails, but the second stage comes off the hose"), this is the internal adjustment that normally only a regulator tech is going to make. On the left side of the diagram, where the hose attaches there is an adjustment that can only be made by removing the hose, and then reattaching it. You can't see the seat and orifice in the pic. If the LDS did this once, it is not uncommon to possibly still need to tighten the resistence knob once yourself.
Once your regulator is broken in, breathing good & with the hissing stopped, it will give you good service for a pretty good length of time. Often by the end of the year the regulator will begin to breathe less efficiently and may start leaking again. Maybe sooner for very avid divers. It is telling you it's time for the annual service.
I hope this helps a little.
Chad
FL Zeagle Rep
(I drew in the + Venturi and - Venturi positions and air path shown by the green arrows, to show students what was going on with the other adjustment.)
Wow, I just noticed this is my 1000th post!
