WaterWolf I've used Poseidon reg's for years ... they was great reg's I loved them because of the easy breathing. If you have dived them much you know they are fin-A-KEY!!!!! I did have two free flows, one at Bonne Terre Mine at 130ft and 43 degrees and the Great Lakes at 150ft at 39 degrees.
Since then I switched to Oceanic. I had a Zeta and talk about easy breathing you got the blast just like the Poseidon's and it breathed for you. But then again it free flowed alot not just in cold water but when ever it wanted to. I had it sent back to Oceanic but it still liked free flowing so Oceanic sent me a FDX-10/DELTA 4.
I started using it and liked it. It's been deep it's been cold. It's been cold and deep at the same time! Zero problems ... thats 0. So picking up a couple more an converting to din and using them in overhead in cold water wasn't a worry.
Then I found the letter from NOAA in Undercurrent and was the first one to post it on Scubaboard you might want to read it. You might be surprized it won out over Poseidon!
Here it is:
Delta4/FDX10 is a great combo for cold water...
The National Oceanic and Atmospheric Administration announced its new regulator pick. In the June issue of Undercurrent, we wrote about NOAA's new rules and regulations for government divers in response to the death of two Coast Guard divers in Alaska last summer. One major change was giving the boot to all regulators Coast Guard divers had previously used for cold-water diving. After testing of multiple regulators, NOAA found Oceanic's Delta IV to be the most reliable.
"It consistently came up first for meeting all our criteria, and it won't freeze up in cold water," says Lieutenant Eric Johnson of the NOAA Diving Program. The Delta IV is an environmentally sealed diaphragm regulator and its first stage has Oceanic's Dry Valve Technology, designed to stop moisture and contaminants from entering and to prevent corrosion of internal components. NOAA bought 350 of the regulators and now requires its 500 divers to use that model when diving in water temperatures of 50 degrees or less. Johnson says the Navy's experimental dive unit is using them, too. The Delta IV is also commercially available for sport divers; Oceanic's suggested price is $570.
Cold-water divers should definitely invest in a good regulator that won't freeze up underwater. Two people died last April because of that problem. Jason Balsbough and Daniel Frendenberg, both age 21, and Sherry Eads, 43, went diving in a quarry in Gilboa, Ohio, where the water temperature was 38 degrees. Another diver called 911 to report the divers were down. Balsbough had regulator problems but was able to surface by himself. Frendenberg and Eads were too deep and their regulators were too iced for them to breathe.