Unbalanced 1st stage and sp D400

[ericpitar]

Hello,

If I paired an unbalanced first stage like the sp MK2 with the D400, would I still get the benefit of easy breathing in most positions especially when vertical and looking up? I'll likely dive only in tropical waters up to 120ft.

 

[Packhorse]

Posistion in the water only effects the performance of the 2nd stage reg not the 1st. So I cant see a problem in that regard.

 

[halocline]

Yes. There's nothing wrong with that combination, although you might offend some SP elitists.

 

[redacted]

The D-400 should still perform up to its high capabilities. The Mk2 may limit your hose routing options a bit and may be challenged supporting 2 divers, one on the primary and one on the octo, in an emergency, especially at lower tank pressures.

Why would you not go with a more capable and flexible 1st stage?

 

[Luis H]

A balanced second stage like the D400 is not affected much by IP change; therefore it will basically perform just as well with an unbalanced second like the Mk-2.

The reason I put the disclaimer “basically” is because even do the IP change will not affect the D400 performance, an unbalance first stage like the Mk-2 is not capable of providing the same maximum flow as most balanced first stages. This is a side effect of the design.

That being said, for most conditions and recreational depth, the Mk-2 provides more than adequate air flow…Just don’t have two excited divers at max recreational depth breathing out of the same first stage.