Mix and match 1st Stage, 2nd Stage and Octo's

[idadd4]

Howdy all - I am wondering about mixing and matching gear. I am looking at getting an Apex XTX200 or maybe an MTX-RC. The problem is, I really like my ScubaPro S600 2nd Stage and my Octo which is an AquaLung.

While I have heard people saying DO NOT mix and match, I am not certain why. People talk "tuning" as the reason, BUT, being a service tech, if the 1st Stage is providing the correct IP which is pretty much standard across ALL equipment vendors, why?

I have done breathing tests with Magnahelix and SCCF tests mixing and matching. I would perform the test with the same gear, then with gear swapped out. I have NOT seen any difference in breathing efforts when swapping. The same breathing effort characteristics carry with each 2nd stage.

What I am wondering is if there is any technical (or factually backed) reasons why you can't mix and match vendors?

 

[inquis]

There are some variations in IP across the industry. However, if the second stages are expecting what your first is delivering, then you're golden.

 

[stiebs]

Nothing wrong with mixing and matching what you've got there - might be pain come service time if your local shop doesn't usually deal with all three brands, service kit availability for all three brands may be an inconvenience.

 

[happy-diver]

I used to be religious about buying only one brand of petrol but kept running out​

It is something I got from my father, that drove for miles and days to buy it cheap​

 

[Mobulai]

Beyond mismatching IP behavior nothing really — and I’m not referring to matching IP tuning, I mean mixing 2 very different animals like Poseidon 2nds that have servos that depend on much higher IP (and how the 1st stage changes IP over tank pressure), or maybe how DH regs (bit I don’t know much about these anyway)
So beyond special cases like this, as everyone said you’re all good (even more so since the 1sts and 2nd you mentioned are balanced and within same IP ranges anyway)

 

[Nemrod]

Balanceed second stages are able to deal with wide variations in IP. Yes, it is best to tune your seconds to match your first stage IP which will itself vary over a tank from full to empty. Balanced second stages are easily able to handle the IP drift of an unbalanced first like the Scubapro Mark 2 Evo, I know this because it is my go to set for most diving and the G250s hooked to it hardly notice the IP change which is considerable compared to balanced first stages.

 

[OMyMyOHellYes]

Europe has some silly weird superstition re: mixing and matching. They have a reg (ulation, not ulator), IIRC, that requires manufacturers to certify 1st & 2nd stages together and those are the only combos "authorized". I've seen some otherwise reasonable, knowledgable folks lose their sh!t over this issue.

See also "weird" and "superstition". Totally unfounded. It's like saying you can only use Toyota oil in your Corolla. You can never use Mobil 1. Or Pennzoil. Or Quaker State. Or Valvoline. Just Toyota branded OEM bottles of oil.

As far as "Balancing"? Really? They think those out-of-the-box new regs are in spec and tuned?

For reference, see again "silly".

There are some weird regs that will not play well withouthere, but as you said if your 2nd is happy with the 1st's IP ... NP.