Piston vs Diaphragm

[Fouremco]

My wife and I are part way through our OW course and researching future equipment purchases. As most of our diving will be done in the Ottawa, Ontario, area spring through fall, we are wondering if we should be looking primarily at diaphragm 1st stages. They seem to fare better in cold water, but by not diving during the winter, I don't know whether or not I need to be concerned with icing. I'd prefer to keep my options open and consider both types, but obviously will concentrate on diaphragm models if necessary.

Any and all comments and advice would be most welcome.

 

[jonnythan]

I like knowing my diaphragm 1st stages are completely environmentally sealed. In my Canadian circle, the Apeks 1st stages dominate.

 

[DA Aquamaster]

Cold water is a relative term. In terms of first stage freeze ups the risk increases as water temp falls farther and farther below about 50 degrees.

Some piston regs are environmentally sealed and some diaphragm regs are not, so it is not a simple piston versus diaphragm issue. Similarly, some unsealed piston and unsealed diaphragm regulators are extremely reliable in cold water while some sealed piston and diaphragm regulators can still be prone to freezing under some conditions. So it is also not a simple sealed versus unsealed issue either.

Finally, it's a matter of freeze resistance in most cases, not freeze proofing and most "cold water" regs will eventually freeze if pushed too hard for too long in too cold of water.

My personal choice is a Scubapro Mk 17 as it has survived some truly impressive freeze testing including sustained high flow rates in near freezing water at 165 ft for 200 minutes without freezing. I have used it in mid to upper 30's degree F water at depth with no issues on some very long dives. The Mk 17 is fully sealed and is optimized for cold water use.

 

[daveg1]

I would go with a good quality sealed 1st stage that you can get serviced at your local dive shop. For recreational diving all the major manufacturers make a good reg.

 

[rescuediver009]

I think that there are many pistons in Ontario. The only thing is to know when and where to use them. I think that the diaphrams are more popular becuse most people want something that they can use all year around. Others may use a piston reg but only during the warmer time of year. Kinds silly, but I think that as mentioned the preferred reg of choice in Ontario is Sherwood (something a little more economical) and the Apeks.