Quote: (Originally Posted by
Dave Sutton)

We actually use 30/25 for the U-Boat guys. You can figure out if we're ANDI or 'other'. Clue: The US Navy labels gas the same way.
I don't know about the navy so here's the alternate educated guess...
130 foot is approx 40m -> P=5Bar
With FO=30% that gives me a pPO2 of 1.5...
For a technical dive (these days!!!) I guess you'll want to stick to 1.4 or lower (25% would give you 1.2-1.3) so the 25 is oxygen and the 30 is Helium right?