Apeks Question

[cnidae]

I know the second stages are the same but the 1st stage is different. The first stage was the only reason I was going with the ATX200's.

 

[Braunbehrens]

The 1st isn't going to make any difference in how wet or dry a reg breathes, otherwise you have serious prolems.

I like the tx50 because you can turn down the necklace reg and stage regs to prevent freeflows. Turn it up when you want to use it.

If you are using helium deep then don't worry about "performance". Shallow you don't need to worry either.

If anything, put your best breathing reg on your stage, 'cause that's where you'll spend a lot of time, typically.

Like someone else said, the differences are going to be so minor, you're better off picking a system and sticking with it. The DS4/tx50 is very popular, but there are others.

BTW, before someone flames me for talking about freeflows on stages, which should be turned off during the dive anyway....the idea is that you charge the reg, then turn off the stage. But then, when you go to breathe from it, you notice that the reg is no longer charged. This is not good, because water could get in, you really want it to stay pressurized.

 

[The Iceni]

cnidae once bubbled...
Are the ports on the DS1 180 degrees apart instead of inline?

Hi cnidae,

As you gathered I used DS1's for my deco bottles. They have one LP port for the second stage and one HP port for the pressure guage. I cannot imagine the need for any other port on a stage bottle (not to be confused with the needs of your argon bottle).

I think the ports are angled at about 120 degrees so the hoses leave the first stage describing a V configuration, which means one or the other (or both) must be looped for storage under the rubbers on the cylinder. As I posted, I consider this to be a minor consideration. (Indeed almost every port configuration on any first stage results in this problem.)

You would be advised to look at other diver's configurations (or actual examples of first stages) and see exactly what you will be getting for your money. After all if all goes well you will be using your purchases for many years and it is best to get it right at the start or it could be an expensive mistake.

The important thing is you have no obligation to opt for the "standard" complete regulator as Apeks allow you to mix and match.

I am not sure what Braunbehrens is trying to say about an uncharged stage regulator. Surely they must be turned on before they can be used at a stop and so will then be charged? At least the stage cylinder will not be happily empying itself during your dive if the stage cylinder has been turned on and then back off prior to the descent, as is standard practice.

I hope my comments have not served to confuse.

 

[cnidae]

"Confused" LOL, I'm totally torn on what to get. At first I was going to go with all Aqua Lung Legends for my back gas and deco's. Then I did'nt want to deal with getting them cleaned for a 100% so I started looking more at the Apeks. Now from what I'm getting from everyone is to not go with the ATX200 becuase there's no benifit and it would be better to have all the same first and second stages for ease of carrying spare parts. As far as the cost is concerned I'm getting the key man program from Aqua Lung so money doesn't really matter because there so cheap, I just want to go with what I'll be happy with. So if you guys were to set up the ideal first and second stage config what would you go with? Keeping your choices limited to Aqua Lung and Apeks.


Thanks

 

[Braunbehrens]

Dr, you asked what I mean, let me try to be more clear in stating the problem.

1) You charge the reg at the surface, then turn off the stage.
2) You do your dive
3) You go to the deco reg
4) You take a breath, hand on the knob of the tank
5) You get about half a breath
6) You turn the knob, and now get a full breath, thereby identifying that you are breathing the right gas.

The problem is that in step 5 above you sometimes get nothing. What has happened is that your reg has somehow become UNcharged. The gas has escaped probably because of a tiny little freeflow when you jostled the stage.

The drawback of this is that your reg may have had water forced into it since it is no longer charged.

All I'm saying is that by using an adjustable reg, such as the TX50 you can turn the adjustment down, which will hopefully prevent this problem.

I hope I'm being clearer this time.

 

[Scubaroo]

Braunbehrens,

I dived with a fellow who would recrack the valve on deco bottles once he had reached depth, to make up for the change in ambient pressure - this was supposedly to assist in preventing water from entering the regulator during the dive while clipped off.

Sort of a steps 1a and 1b - descend to depth, crack valve to recharge

 

[Braunbehrens]

Problem is that on some regs they tend to "let out" a little gas now and then. If you continually crack the valve to repressurize, you end up using quite a bit of gas.

The other issue is that if you crack the bottle at 200 ft, (6-7 ATA) and then don't breathe it until the 20 ft stop you create an IP of 200 psi or so. Probably not the best thing for the reg to do on every dive.

If the reg stays pressurized then charging it on the surface should keep positive pressure down to 250 ft or so at least.

 

[The Iceni]

Braunbehrens once bubbled...
. . . The drawback of this is that your reg may have had water forced into it since it is no longer charged. . .

All I'm saying is that by using an adjustable reg, such as the TX50 you can turn the adjustment down, which will hopefully prevent this problem.

Hi Braunbehrens,

I am no instructor so perhaps my ideas are wrong but leaving a stage bottle charged during a dive risks losing the gas even with a cracking resistance turned right down, so this manoeuvre seems pointless. Hence the recommendation to turn stage bottles off after charging and checking the regs during the buddy check pre-dive.

I suspect most commonly the purge button gets knocked somehow causing the supposed "leaks" you describe.

I admit this could be a problem, but I am not sure how a significant amount of water (at even 4 bar) could ever be forced upstream of the second stage unless there is a major, rapid, leak that completely discharges the regulator in the short time it takes to descend on a dive. In such cases you are effectively descending with a discharged regulator - bad news possibly requiring a full service. I am not sure of the reason the chap described recharges his stages at depth as the intermediate pressure should be more than enough to prevent any water ingress, if there are no major leaks.

Isn't it more sensible to

1) charge the reg at the surface, check it works without the guage needle moving, then turn off the stage,
2) do your dive,
3) approach the stop using current (bottom) mix,
3) identify the deco bottle and reg required by sight and feel,
4) turn it on,
5) change to breathing from the reg you know is attached to the bottle you just turned on?

I suggest that taking even half a breath from the wrong stage reg is not a good idea. I can imagine the panic and a rapidly approaching incident pit if you find yourself unable to continue breathing from the regulator in your mouth that is actually attached to a different cylinder from the one you have just turned on.

I believe it is far better to be certain of the gas you are about to use before you turn the valve on or breath from it.

I have not been taught any other way but may stand corrected as my area of expertise is not instruction. :doctor:

 

[Braunbehrens]

I thought I specifically said in my post that in step 1 you turn off the stage after charging it.

Once the stage is off, the IP can't go up anymore. So if your IP is 150, that's about 10 ATA. Add surface pressure so make it 11 ATA. Every 30 ft is 1 ata, so at 300 ft the IP has dropped to zero.

ATA = atmospheric pressure, roughly 15 psi.

Taking one breath from the wrong cylinder is not that big a deal. Chamber rides are often done with O2 at 60 ft, and I known someone who used to sit at 60 ft in the ocean breathing O2 for medical reasons.

In any case, the reason you have the stage off and turn it on after identifying it, is to prevent breathing the stage for several minutes at the wrong depth. I like the added security of takign a breath and making sure that I'm turning on the right stage. If you just take a breath and have already turned the stage on, can you be sure that you are not breathing another stage that happened to be on?

If taking half a breath, knowing that you need to turn on the stage, and not getting a full breath causes you to freak out, then you shouldn't be doing any dives, definitely not deco dives. I don't mean to single you out or be offensive or anything, but that is a very very minor thing to have happen under water. You have at least 2 other working regs, one around your neck.

Gotta go.

 

[The Iceni]

Braunbehrens once bubbled...
Once the stage is off, the IP can't go up anymore. So if your IP is 150, that's about 10 ATA. Add surface pressure so make it 11 ATA. Every 30 ft is 1 ata, so at 300 ft the IP has dropped to zero.

Hi again Braunbehrens,

Now I see where we are both getting confused. Even at the extreme depth of 300 ft (say 90 metres) where the external pressure is 10 ATA, this is still less than the intermediate pressure of 11 ATA . So for all practical purposes in recreational scuba the IP of a leak-free charged regulator will always exceed ambient pressure thus preventing the ingress of water through any leaks.

On the other hand, if the regulator is discharged the IP will drop to close to ambient pressure. At the surface this is about 1 ATA . When this discharged regulator is then taken to depth there will exist a pressure gradient risking contamination of the regulator through any leak.

I think on this we are in violent agreement!

If you just take a breath and have already turned the stage on, can you be sure that you are not breathing another stage that happened to be on?

Check first, surely?

4) identify the deco bottle and reg required by sight and feel,
5) turn it on,

QED