Mixing second stages

[vicky]

Is there any problem connecting different 2nd stages? For example: 2nd stage and Octopus from the same brand, but different models?
2nd stage and Octopus from different manufacturers?

Thanks,
Vicky

 

[Ber Rabbit]

I have a Scubapro MK10 with 2 G200 2nd stages instead of a designated "octopus". I was told when I bought the regulator (used) that the octopus used to be a different model but had been replaced with the same model as the primary 2nd stage. I also have a US Divers Conshelf 22 with a US Divers Conshelf 22 primary and a US Divers Octo octopus. The only difference I see with my gear is the G200 I'm using as an octopus will free flow sometimes if I am doing a giant stride entry from something high, like a boat. I keep the breathing ease setting at the maximum effort position to prevent free flows while I'm diving. The US Divers Octo doesn't free flow even when I intentionally smack the purge button on the water's surface because it's designed to be a secondary 2nd stage (spends most of its time out of the diver's mouth) so it's harder to get air out of it.

Both rigs work fine for me, I just have to make sure the G200 is set to max breathing resistance. Others on the board are knowledgeable in this area, I'm simply letting you know that "mixed" 2nd stages works for me.

Ber

 

[Lost Yooper]

Not generally, no.

Mike

 

[scorpiofish]

It's been a long time since any of my regs matched the octopus.

If the LDS says you need to maintain brand integrity, they are full of crap. Hell, even our rentals are mix and match.

There are a few exceptions. The key is that the both the primary and secondary be able to work off the same specification of intermediate pressure from the first stage.

Get whatever you want.

 

[Corsair]

Personally, I've been nothing but happy with the setup I bought. It consistsof an apollo first stage with their nifty biofilter. an Atomic primary second, a mares hose on the Apollo Octopus and a Tusa console and gauges.

So far it has been an excellent rig.

 

[Norm]

Vicky I do not think that you will encounter any problems with any mismatches that you may make. To my knowledge, only a few select models of Poseidons are out of range for any other reg manufactured today. As long as the threads match and the intermediate pressure is close, they usually work fine.

 

[The Chairman]

The Poseidon is one of the few regs on the market today that employ an "upstream" second stage regulator. Consequently, they come equipped with a pressure release valve on the first stage. You can dial down the IP on the first, and any second stage should work fine on this reg. HOWEVER, the converse is NOT true. No Poseidon Second stage should ever be the only type of second stage reg on another make first stage. Without a safety vale (as is afforded by a downstream design) you can have dangerous pressures in your regulator hose. If you use a Poseidon as a second stage, then use a downstream style reg as your octo, or fit your first stage with a relief valve.

 

[CanyonDiver]

I use a Jetstream second stage with a SP MK10 first stage for my deco reg.
The only thing i notice is a little more resistance that normal upon inhailing. What is wrong with this?

 

[The Chairman]

Breathing resistance is not the issue. A downstream style second stage regulator is a built in safety valve. Thats why they free flow when the first stage boogers up. Poseidon second stage regs use an "upstream" design. Consequently, they do not provide a default safety valve and you should have one in the first stage. The other way of doing this is to have a secondary (octo) second stage to be your safety valve. Without it, when the first stage starts to free-flow, there will be an unsafe buildup of pressure in the regulator hose.

Poseidon regs are super regs, and I use two of their first stages. I am in no means trying to rag on a manufacturer, but you have to be careful with your franken-regs.

 

[CanyonDiver]

Ok I understand about the pressure buildup. The jetstream second stages have an over pressure bypass built into the hose.
if you pull the hose away from the second stage while under pressure you will hear air escape out.