Is LDS correct concerning 1st & 2nd stage mixing??

[DiveBen]

I am interested in replacing my Ocenaic GT3 with, possibly, a Aqualung Titan LX series or Aqualung Legend series regulator. My first stage is an Oceanic CDX5. Type of diving I mostly do is in the 40' to 60', with some occassional 100'+/-.
I feel that my CDX5 is a good 1st stage, and it is also balanced (I believe it is actually "overbalanced").

I was discussing the change at a dive shop today. The salesman told me that I should not just replace the second stage with different brand 2nd stage, than my 1st stage. He informed me that manufacturers design both stages to work together, and so, you may compromise performance by mixing the CDX5 with a second stage from those mentioned above.

Anyone have any insight as to whether that is actually true or not? The 1st stage on, say the Titan LX, is balanced, but I believe my CDX5 is "overbalanced". Just sounds like performance would be better from my CDX5 as a 1st stage. Not only do I not have issues (that I'm aware of) with my 1st stage, but it would be nice to safely save some $$$ by buying only a 2nd stage for upgrade.
By the way, the only reason I am considering the change at all, is that I would like a reg that breathes better at the 90+ depth. My GT3 is okay, but I find it just doesn't "breath" as well after about 85 or so feet.

Ben

 

[Jorgy]

I believe that most modern first stages and most second stages will work together....

I have mixed Aqualung second stages on ScubaPro and IDI first stages....

I also have a Sherwood Gemini Octo/Inflator that has worked well with all my first stages...

I also own a Poseidon rig that I don't mix stages on......

The downside to a mixed reg is getting it serviced....make sure that your LDS can service both or you will need to take it to different shops.....

Before you buy a new second stage have you had the reg fine tuned? It might be worth it to have it checked.........

M

 

[Bubbletrubble]

I don't have any experience servicing or using Oceanic regs, but I might be able to provide some general reg info.

The Oceanic CDX5 is a balanced diaphragm first stage that is environmentally sealed. It doesn't have any sort of magic inside that only works with Oceanic second stages. You should be able to use any second stage you want...so long as the second stage can be tuned to accommodate the i.p. delivered by the first stage.

That being said, getting your reg serviced will be more convenient if the first and second stages are from the same manufacturer. If you had a reg setup with an Oceanic 1st and Aqualung 2nds, you would probably have to find a reg repair shop that services both Oceanic and Aqualung regs. Both are large companies, so I don't think it should be too difficult for a local shop to service your regs, though.

AFAIK, the GT3 is a balanced adjustable second stage. I suspect you should be getting better performance out of it. Along these lines, I have a few questions for you...

Could you describe how breathing off of the GT3 at depths greater than 85 fsw is less than optimal?
Does it not provide enough gas once flow is initiated...or is it difficult to start the flow of gas?
What is the current i.p. being delivered by the CDX5 first stage?
Is this i.p. within manufacturer recommended limits?
When was the reg setup last serviced? (Is it due for servicing?)
What is the cracking pressure (inches of water) of your GT3 currently?
A cracking pressure of approx. 1.0"-1.2" inches of water should breathe fairly "easy."

Or, rather than answering all of these questions, you could do what the vast majority of divers do when their regs don't live up to expectations. They take 'em into a local repair shop and ask them to do a reg tune-up.

Hope this helps...

 

[Stu S.]

The Oceanic is a really good regulator. You can contact them on this board if you have questions. A simple adjustment may make a pleasing difference.

 

[Garth]

My opinion for starters.... Oceanic is not a good regulator... (my opinion)

If you want to save money and have a good regulator... Buy a few HOG regs.

Again... My opinion. Based on personal experience with a friend and his oceanic (his survival situation). POS. IMO.

 

[Ana]

I happen to have a CDx5 first stage. It has been a magnificent regulator for me. Don't remember when I got it (bunch of years) and I've mixed 2nd stages from Oceanic and other brands.

Coincidentally today was its turn to get it serviced, we bought the kit yesterday and after a good soak to get all the insides clean, took very little to put it back together. I have both the yoke and DIN versions, I switch when I go on trips and have to rent a tank.

By the way, I wouldn't trust just any dive shop to service my regulators, it isn't rocket surgery to do it yourself. Learn to do it, get the few tools needed and then you don't have to wonder if the guy that did it, got distracted and pinched and O ring, or just rushed setting the intermediate pressure and is going to start creeping. Exactly because it isn't that difficult of a task, sometimes these shop "technicians" do not pay the needed attention.

Don't know if I got lucky but my CDx5 is not a POS, it is actually pretty decent, has been delivering gas in a very nicely in all my dives, many of then bellow rec limits. Now that I think about it, it is probably a very decent regulator since I don't baby it at all.

I don't service it every X months, there are times that after a couple of years the thing breathes perfect and I don't see a need to mess with it. When I feel that is not delivering like it should, or like today when I'm going to change from DIN to YOKE and appears kind of dirty then is when the deep cleaning and service gets done.
I'm not very good a rinsing it after each and every dive either, I just give it a good rinse if its going to be dry for several weeks. My philosophy is that gear that remains wet remains working.

To the OP go ahead an get whatever 2nd stage you want, but maybe also consider if it may be time to service the 1st stage.

 

[larry mckinnon]

I agree with Ana, If your regulator is working great, leave it alone, but make sure you keep it clean. My son in law has a 20 year old regulator that he has maintained himself, never rebuilding it, just taking it apart and cleaning it after every dive trip. He has never had a problem, free flow, change in the breathing. I myself have always taking my regs in for others to work on when i think they need service. Last time i took my reg 1st and 2nd in it cost me $140.00. I agree with those of you that are going to say I would think that is very cheap if it were to go out the first day of a week long dive trip, or worse, when at 100 feet. I just like the idea of being responsible for my own gear, and I were to have a problem, because I rebuilt it myself, I would be in a better position to fix things myself on the spot. It is not really an issue of saving money, it is an issue of being responsible for yourself. I am going to take responsibility from now on.

 

[theduckguru]

I am interested in replacing my Ocenaic GT3 with, possibly, a Aqualung Titan LX series or Aqualung Legend series regulator. My first stage is an Oceanic CDX5. Type of diving I mostly do is in the 40' to 60', with some occassional 100'+/-.
I feel that my CDX5 is a good 1st stage, and it is also balanced (I believe it is actually "overbalanced").

I was discussing the change at a dive shop today. The salesman told me that I should not just replace the second stage with different brand 2nd stage, than my 1st stage. He informed me that manufacturers design both stages to work together, and so, you may compromise performance by mixing the CDX5 with a second stage from those mentioned above.

Anyone have any insight as to whether that is actually true or not? The 1st stage on, say the Titan LX, is balanced, but I believe my CDX5 is "overbalanced". Just sounds like performance would be better from my CDX5 as a 1st stage. Not only do I not have issues (that I'm aware of) with my 1st stage, but it would be nice to safely save some $$$ by buying only a 2nd stage for upgrade.
By the way, the only reason I am considering the change at all, is that I would like a reg that breathes better at the 90+ depth. My GT3 is okay, but I find it just doesn't "breath" as well after about 85 or so feet.

Ben

If I were going to buy a Legend 2nd stage, I'd buy both 1st and 2nd stages and keep the Oceanic 1st/2nd as a back up, but my reasoning has nothing to do with incompatability.

 

[Jim Lapenta]

I have two CDX5's. Both have been to 150 feet plus in 38-40 degree water. I also have two HOG D-1's. I had a minor issue with one of the D-1's on trip and didn't feel like messing with it and missing a dive. Just swapped it with one of the CDX5's. All of my regs are set at an IP of 142 give or take a psi or two. Swapping stages in no big deal. Servicing different makes can be an issue if the dealer or you can't get parts for both. But as for the BULL CRAP about stages being designed to work with each other? Tell em to set the IP's the same, tune the 2nds to match and shove their line of garbage.

 

[Damselfish]

If 1st & 2nd are different brands it could be less convenient to get service, if your LDS doesn't service both brands. But any LDS that says you should buy both the same for compatibility reasons, instead of replacing one stage, is most likely wanting to make a bigger sale.