regulator/octo brand correllation?

[nothanx2]

hey guys, im a new guy here and to scuba in general, slowly getting my own equipment together, and i had a question you guys might be able to help with.

Some folks have said you should (or have to) keep the brand of regulator/octo the same for both, whereas some people say and have regs that are totally mismatched and they have no problems. Personally i think that its reasonably possible for some brands to be incompatible and others to be fine with each other. any answers, thoughts, input. just for reference, im going to be doing fairly cold water beach diving, within rec limits, and often in not the greatest conditions. and right now im looking at scubapro, atomic, apeks and aqualung regulators. thanks a bunch.

eric

 

[DA Aquamaster]

Nearly every scuba manufacturer uses downstream regulators designed to operate an intermediate pressure range of 120 to 145 psi. Poseiden would be the most noteable exception.

So it usually not a problem at all to mate an octo from one brand with a regulator of another brand. Ideally, even with reg/octo combinations of the same brand, you should have the octo tuned to the specific first stage. But most octos are factory set to have ahigher than average cracking effort so generally an IP at the upper end of the range is not a problem and will usually not result in a free flow. Still, for peak performance, the octo should be tuned to the first stage.

The potential downside of mixing and matching is that you then need a shop that handles both brands to do a proper annual service. So mix and match away but stick with equipment that you can get serviced locally without having to go to two different shops.

Scubapro, Aqualung Apex and Atomic are all great companies that make great regs. Scubapro and Aqualung/Apex have wider dealer networks and their regs are generally easier to get serviced than Atomic. Scubapro and Aqualung also have excellent histories of providing parts and service support for decades, so there is no need to worry about them discontinuing a reg and leaving you hanging.

 

[knotical]

I agree with DA Aquamaster. I am one of the many who often dive with mixed brands.

And now a question for DA Aquamaster: Would combining an Aqualung Legend first stage with a traditional octo (or even primary second) be another possible exception to the general rule? Aqualung says their Legend first stage is “overbalanced”, and that their IP “increases at a rate faster than the traditional balanced models”. i.e. instead of staying at (say) 135 psi above ambient, it would be more than that at depth. If this is so, it seems that a traditional second would either free flow at depth, or have to be adjusted so that it would be much harder to breathe at shallower depths. Not surprisingly, Aqualung recommends you buy their Legend octo too.

 

[DA Aquamaster]

I only see a few ledgends come through the shop each season and I am by no means an expert on them.

I suppose it could be an issue with an unbalanced octo if the total increase in IP relative to ambient pressure were more than 20 psi or so and/or if the cracking effort on the octo was set fairly light.

I would be surprised if it were an issue with a balanced second stage as while they are biased toward the downstream side, they are not so heavily biased that a moderate increase in IP would cause a problem unless again they are set with the cracking effort extremely light. A diver adjustable cracking effort knob on the second stage would also provide a solution to any problem that may develop and would again allow the second stage to be set with a minimal cracking effort.

The effect of the IP increase with depth that occurs with an "overbalanced" first stage on second stage performance and tuning is in my opinion the principle drawback of that design approach. I personally don't think the small increase in flow rate at depth that results is worth the complications and potential limiting effect on minimum cracking effort that can potentially occur. If the reg is delivering adequate air already, a diver will never notice the slight increase in flow rate, but will always notice when it breathes harder in some circumstances than a comparable performing traditionally balanced reg with a stable IP.

 

[rescuediver009]

To add, to DA, he has it right, and I also strongly recommend a balanced octo with an overbalanced first stage. I also recommend the samebrand name only because it will simpluify your service trips in the years to come. And unless you are in love with a particular octo, you will likely be able to find something that closely matches your taste.