First Regulator Set Purchase

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Also the Subgear line is made and serviced by Scubapro (you can ask Casey) and is cheaper also. However, I think the A700 is a better second stage than what Subgear offers.

---------- Post added August 12th, 2015 at 12:18 PM ----------

What do you mean by maintenance? In my experience the rinsing soaking is the same because you still need to soak the second stages because water does get into the internals. If you are talking time between overhauls that depends on the manufacturer and the parts in the kit. BTW, there are other attributes of performance to look at, such as air flow and IP stability. A MK-25 flows more air and is more stable than a MK-17. There was a thread a few years back discussing the IP swing of a MK-17 between a full and empty tank, you can take a look at it if you are interested. You forget the unsealed diaphragm which are far more numerous than the sealed versions. These have been dived safely for years too.

In an attempt to be more clear, I'll try again. Lets pick a balanced piston (unsealed) at one extreme and a balanced sealed diaphragm at the other. Again we're talking about first stage only and using IP stability as the measure of when a rebuild is warranted.

Which, in your experience, requires a shorter service interval. (I had thought the MK17 was a balanced regulator, thanks for the education)
 
that in the end and how much it would cost to service an atomic every 2 years, and the according to scubapro website it has 2 years/dives on regulators. I don't think I would have more then 100 dives in a year. What do you guys think?
Personally parts/service costs are not a major consideration for me. I dive Atomics and my costs are in line with what I read others pay here - always around $100-110 or slightly less for everything - 2 stages, octo, parts and gauge spool/o-rings. A little more if I go to the other dealer in town.

One difference is that Atomic is 2 years/300 dives while Scubapro is 2 years/100 dives. 100 dives is the service interval, it's not per year.
What is the current service cycle for my regulator?

SCUBAPRO regulators need to be serviced every 24 months or 100 dives, whichever comes first, by an authorized SCUBAPRO dealer.
I can't fault your choice though it would be on my list if I dove in cold water. Personally I'd go with a G260 but IDK really know why. Probably because unlike most, I don't like metal 2nd stages.

Is your deal better than this?
 
Well I had decided on the MK17/A700 and Casey from Beaver Divers helped a ton in getting me the other gear that I was looking for as well, for a fantastic price! Buying them all separately would of cost me over $1300, and was able to get it for much less then I was anticipating! I was communicating back and forth with him for the past 36 hours or so. So my first regulator set includes, a new ScubaPro MK17, new ScubaPro A700, new ScubaPro R095 Octopus, and a lightly used 4 dive recorded only Subgear 3-guage, XP-10 (Computer, Pressure Gauge, and Computer) Console. I have to say I completely satisfy with the customer service that Casey displayed and he even went up and beyond and called up a ScubaPro rep to get answer for that I asked about eh MK25 EVO. I can honestly say I will differently buy from Casey again! When I look for other gear as I need it! I also appreciate all the responses that you all provided and was very beneficial in helping me make decisions based on information I didn't know!
 
In an attempt to be more clear, I'll try again. Lets pick a balanced piston (unsealed) at one extreme and a balanced sealed diaphragm at the other. Again we're talking about first stage only and using IP stability as the measure of when a rebuild is warranted.

Which, in your experience, requires a shorter service interval. (I had thought the MK17 was a balanced regulator, thanks for the education)

The MK17 is a balanced regulator, meaning it does have a balance chamber. But it is not fully balanced; there still is significant upstream bias, so the IP rises as the tank pressure decreases. With a high performance balanced 2nd stage most people don't notice this as the 2nd stage compensates for changes in IP to a degree.

But this is not the same thing as "IP stability". Unstable IP due to wear on the seat is always experienced as IP creep, meaning the reg does not lock up quickly and stay put after each breath. The rise in IP over the supply range in the MK17 is by design, it will do it when its brand new or 5 years after a rebuild.

If you are going to compare piston to diaphragm regulators, you have to consider that flow through (balanced) and flow by (unbalanced) piston regulators are very different in design and function. Some flow by regulators are famous for tolerating abuse and lack of maintenance for years.

Pistons are stainless steel and as such are very unlikely to rust, but there is some validity to the idea that bits of crud can contaminate the HP o-ring on the ambient chamber side in some flow through piston regs. Most of the newer ones (like the MK25) have bushings that tend to protect the HP o-ring, and I've seen MK25s go for many years before creeping. The classic USD unsealed diaphragm design has likewise proven itself to be VERY stable and tolerant of lack of maintenance.

In all unsealed regulators, piston and diaphragm, there's an ambient chamber where water goes, and water does not penetrate any further. In piston regs, a portion of the piston shaft and head, the spring, and 2 o-rings are in this chamber and exposed to water. In diaphragm, only the spring and diaphragm (and maybe a spring pad) are exposed. So one might think that diaphragm regs would need less maintenance as a rule, but there are lots of other factors. Exposed threads are present in both designs, and diaphragm regs have that tiny HP o-ring in the balance chamber.


I have MK5s that are going on five years without any sign of creep, I've seen MK25s go for similar lengths, and I don't think I've ever rebuilt my MK2; I don't use it much, but I've had it for at least 10 years. So piston regs can certainly hold up.

If I were offering advice about getting regulators that can go the longest without maintenance, I'd say it's more important to get one of the classic designs that has has proven itself over decades of use than it is to choose a diaphragm over piston or vice-versa.
 
Well I had decided on the MK17/A700 and Casey from Beaver Divers helped a ton in getting me the other gear that I was looking for as well, for a fantastic price! Buying them all separately would of cost me over $1300, and was able to get it for much less then I was anticipating! I was communicating back and forth with him for the past 36 hours or so. So my first regulator set includes, a new ScubaPro MK17, new ScubaPro A700, new ScubaPro R095 Octopus, and a lightly used 4 dive recorded only Subgear 3-guage, XP-10 (Computer, Pressure Gauge, and Computer) Console. I have to say I completely satisfy with the customer service that Casey displayed and he even went up and beyond and called up a ScubaPro rep to get answer for that I asked about eh MK25 EVO. I can honestly say I will differently buy from Casey again! When I look for other gear as I need it! I also appreciate all the responses that you all provided and was very beneficial in helping me make decisions based on information I didn't know!

Congratulations - I think you will really enjoy these regulators. Scubapro is a solid company that has stood the test of time. I have used their regulators for 20 years and they have always been very reliable and real workhorses.
 
Look real hard at Poseidon also if you have a dealer in your area also. Here's why:

TECHNICAL FEATURES:
> Trimix, nitrox, oxygen and air
> 95% Helium mix could be used
> 100% O2 Certified
> 200 m / 656 ft approval Norwegian Norsok U101 standard
> Approved to cold water standard, EN250
> Approved for use under ice down to -1,6 °C / 29.12 °F without CWD kit
> Unique internal Thermo Dynamic Anti-freeze system (TDA)

> 5 LP and 2 HP-ports

View attachment 214494

Poseidon XSTREAM Deep MK3 DIN Regulator, Black 0100-000 - $719 in this configuration.

I personally don't dive under ice but I believe you can overbreathe a piston regulator while doing so causing it to freeze up.

Starts and ends with Poseidon or me too. Last regulator you will ever buy if you want it that way.

That being said there are some there are some tradeoffs.

Side exhaust takes a little getting used to. But after that bottom exhaust seems weird.
Parts and service can be a challenge. Don't expect to take it in a week before your big trip and have it ready.
Uses special hoses or an adaptor for the downstream design.

But the most consistent easy breathing reliable reg I have ever used.

I am sure all top end regulators have their ardent fans. You really cant go wrong at the top end of the market.
 
In an attempt to be more clear, I'll try again. Lets pick a balanced piston (unsealed) at one extreme and a balanced sealed diaphragm at the other. Again we're talking about first stage only and using IP stability as the measure of when a rebuild is warranted.

Which, in your experience, requires a shorter service interval. (I had thought the MK17 was a balanced regulator, thanks for the education)

Halocline gave an excellent answer to your question, so I will not repeat what he said. In my experience (using non-defective parts) they are equal.

BTW, I am not advocating piston over diaphragm. I am questioning the need for a "sealed" first stage. Sealing is advantageous for diving in extreme cold or polluted (the chemicals could react with the o-rings) waters, but this describes a very small minority of the diving public. Usually the best "value" (mix of price and performance) is in midpoint of the manufacturer's product line and usually these regulators are unsealed. For example, looking at Scubapro an unsealed MK-11/S360 is $409.00 while a sealed MK-17/G260 Tactical is $699. The difference in performance between the two in the real world is negligible. Aqualung is better in that you can purchase the Core in either an unsealed or sealed version for a difference of only $30 ($460 vs $490). For $30 I would probably recommend it as it would have better resale.

As of late people are touting the advantages of sealed regulator while ignoring the fact that people are diving unsealed regulators that are 30, 40, or even 50 years old that are still going strong.
 
Sealing is advantageous for diving in extreme cold

I've been doing some reading and wondering about this point. Particularly after I had 3 separate free flow incidents on the same day, from 2 different 2nd stages, while using a sealed diaphragm 1st stage in 38F water (and was breathing really hard, admittedly). I originally thought it was because my 2nd stages iced up. But, the more I've replayed the incidents, the more I think that it was (or, at least, could just as easily have been) an iced up 1st stage.

I've been emailing with a diver who is VERY experienced with very deep and very cold. He avoids sealed first stages for really cold. His explanation is that it's always going to be negative (below 0C) inside the reg (at least, in the context of cold water diving). Water that circulates into the 1st stage will, by definition, be warmer, thus delivering heat into the reg. Sealing the water away prevents it from warming the internals of the reg.

I responded with, "but if you keep the water out, how would it ever ice up inside?" His answer was that even the best fills will generally have SOME moisture in them. He's had people with free flows whose tanks were measured and found to be just barely under the limit (not sure whose) for scuba tank air moisture content. The free flows were from ice that came from moisture inside the tank, not from external water.

The bottom line (my interpretation of him): if your tank gas has 0 (ZERO) moisture in it, you won't get a free flow from icing in the 1st stage, no matter which type you have. But, if you do have ANY moisture in the tank air, then having a sealed 1st stage will just keep the (above 0) water from circulating inside and warming the internals, so you'll be more likely to get ice inside and a free flow.

That all seems to make sense to me, but I'm curious about other opinions.
 
Water that circulates into the 1st stage will, by definition, be warmer, thus delivering heat into the reg. Sealing the water away prevents it from warming the internals of the reg.

Ocean water freezes at 28 degrees because of the salt content.
 
I just wanted to add about Casey at Beaver Divers, he was able to help me get a new ScubaPro BCD as well with my regulator set to sweeten the deal. So all in all I got about $2000 for sweet deal that i couldn't pass up and Casey answered every single question I had as they popped up. I have never seen customer service like this ever in any retail business!
 

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