Mixing Balanced and Unbalaced Regulators

[certainmisuse]

Hello,

Pardon my naivete with regards to regulators. Are there any issues with pairing a balanced first stage with an unbalanced second? I'm looking at getting a ScubaPro R195 with a 1st stage that has at least 2 HP ports (for example, the MK17) and they are all of the balanced variety. I previously had an R295 with an MK2 which suited my needs at the time. Looks like they don't produce the R295 anymore. Later I will likely move the R195 to a backup or pony bottle.

Thanks everyone.

David

 

[northernone]

Hello,

Pardon my naivete with regards to regulators. Are there any issues with pairing a balanced first stage with an unbalanced second? I'm looking at getting a ScubaPro R195 with a 1st stage that has at least 2 HP ports (for example, the MK17) and they are all of the balanced variety. I previously had an R295 with an MK2 which suited my needs at the time. Looks like they don't produce the R295 anymore. Later I will likely move the R195 to a backup or pony bottle.

Thanks everyone.

David

Those will play nicely together.

Enjoy,
Cameron

 

[herman]

Not a problem at all.
I prefer one stage or the other to be balanced but in the end, any combo will work fine.

 

[rhwestfall]

either is fine, both is "belt and suspenders"

 

[Brian G]

To explain a bit more, a "balanced" regulator (either first or second stage) uses the high pressure side to compensate for changes in pressure as air gets depleted. So, in a balanced first stage, the intermediate pressure will stay fairly constant as the tank pressure drops. In a balanced second stage, the breathing effort will stay constant with varying intermediate pressure. If you have a balanced first stage paired with an unbalanced second stage, your breathing effort will stay constant because the balanced first stage is keeping the intermediate pressure constant. If you have a balanced second stage paired with an unbalanced first stage, then your breathing effort will also stay constant because the balanced second stage is making up for the changing intermediate pressure from the unbalanced first stage.

In short, absolutely no problems mixing the two types.

 

[kensuf]

It depends on the first stage.

The MK17, probably no problems. A MK25, probably no problems. An Apeks DS4 or DST, you may have problems at depths greater than 200' because of the way the IP goes up on an Apeks first stage. The solution is to remove the Apeks environmental cap (or use the US4/UST first stages).

 

[kensuf]

And by problems, I mean you may get a freeflow.