MK25 LP ports?

[jarmar]

Yes, you are right. Sorry, I was thinking about HP.

 

[Puffer Fish]

The difference is in the depths and temps where the test occurs. Being 5 ft deep in an 80 degree pool does not mean much. It's also a bit like the "20% more flow from the top LP port" comment - at some point how many more divers it will support is irrellevant.

Tests like that are also misleading as the limiting factor in the real world is the second stage. You can only flow so much air at a given pressure through an orifice of a given size so even a very high performance second stage will have a limit of about 65 SCFM.

I suppose it's comforting that the 300 SCFM flow rate of the Mk 25 would enable me to continue to breathe while 4 other buddies depress the purge valves on 4 other second stages attached to my Mk 25 (I suspect the ability to actually do this is the real reason for the 5th LP port) but at 300 SCFM, the comfort would be short lived even with doubles.

You need the 4,400 psi, 15,000 L tank and you should be good to go.