Scubapro Regs... What's the difference? Which one to get?

[Kamala]

I'm having a hard time differentiating between the scubapro regs from a usability standpoint. Academically, I understand the differences, but as a novice diver, I'm not getting how the differences will help/hinder me underwater. I will be doing increasing amounts of diving in the Puget Sound (50ish F water year-round, 40-80 F air Temp), but will be using the same set-up for travelling to the tropics.
I'm considering all of the following (knocked off the MK25T/S600T because it's way out of my price range.)...

MK25SA/S600
MK25/S600, X650, G250, S550
MK16/S550, R390

From what I understand, it may also be possible to get the MK16 with the G250, X650, and S600. If that is indeed possible, would the MK16 be better than the MK25 if I choose one of those second stages?

If it helps, I dive a Scubapro Knighthawk and use an octo set-up, not an Air2. Thanks!

 

[divematt]

I'm glad you asked this question as my girlfriend and I are in the same situation. We both want new Scubapro regulators but don't know which ones. I'm leaning very heavily toward the MK25/ X650, as I now have a 12 year old G250 which I love. I was thinking of having my girlfriend get the G250 as she does not want to spend much more. Is it foolish to not get the MK25 if you're going up to the G250 level or above? How big a difference would it make if you did use the MK16? Also as far as the 600/ 650 debate, what are the pros and cons of each of these against each other? I like the idea of the exhaust going out of the bottom of the reg away from your face. By the way, does the 650 and 600 breathe easier than the 250? I'd really appreciate any input as reading the Scubapro manual doesn't tell me enough.

Thanks,
Matt

 

[brucebowker]

I'm glad you asked this question as my girlfriend and I are in the same situation. We both want new Scubapro regulators but don't know which ones. I'm leaning very heavily toward the MK25/ X650, as I now have a 12 year old G250 which I love. I was thinking of having my girlfriend get the G250 as she does not want to spend much more. Is it foolish to not get the MK25 if you're going up to the G250 level or above? How big a difference would it make if you did use the MK16? Also as far as the 600/ 650 debate, what are the pros and cons of each of these against each other? I like the idea of the exhaust going out of the bottom of the reg away from your face. By the way, does the 650 and 600 breathe easier than the 250? I'd really appreciate any input as reading the Scubapro manual doesn't tell me enough.

Thanks,
Matt

Difficult to answer all your questions but perhaps I can help with some. The S600 is a smaller vesion of the G250. Does it breath easier? Doubt there is much noticable difference at all. I had a G250HP and now have and S 600 and can't really say for sure there is much difference. The Mk 25 and the Mk 16 are both good with any 2nd stage although I would not spend the money on a MK25 and then use an R190 2nd stage. The Mk 16 is said to be better in cold (very cold) near freezing water but I can not attest to any of that. When the water gets below 80 here I think it is really cold. I do find the Mk 25 to be a very good regulator .

As far as where the air exits a 2nd stage, going out the bottom only means the bubbles will rise anyhow and most lilkey hit your face. Strange to what seems to be a serious problem with many divers, but bubbles from ANY regulator have never bothered me. I have taken enough pictures too. They all exit close to ones face and some will have to go past your face sooner or later. No regulator except a double hose keeps bubbles 100% away. Side exits, bottom exits, they all are close.

Bruce Bowker
Bonaire

 

[brucebowker]

I'm having a hard time differentiating between the scubapro regs from a usability standpoint. Academically, I understand the differences, but as a novice diver, I'm not getting how the differences will help/hinder me underwater. I will be doing increasing amounts of diving in the Puget Sound (50ish F water year-round, 40-80 F air Temp), but will be using the same set-up for travelling to the tropics.
I'm considering all of the following (knocked off the MK25T/S600T because it's way out of my price range.)...

MK25SA/S600
MK25/S600, X650, G250, S550
MK16/S550, R390

From what I understand, it may also be possible to get the MK16 with the G250, X650, and S600. If that is indeed possible, would the MK16 be better than the MK25 if I choose one of those second stages?

If it helps, I dive a Scubapro Knighthawk and use an octo set-up, not an Air2. Thanks!

You can get a Mk 16 with the 2nd stages you mentioned. The only real advantage to the Mk 25SA is that it would be lighter. People traveling say it helps because it is lighter but you are not looking at 10 pounds, more like onces. A titanium is a different story and I usually recommend those to people (mainly professional divers) who can't, don't, or refuse to keep a regulator washed. They will look the same after 10 years as they do now. But insides are all same as a regular MK 25. The S550 is an S600 without the adjustment knob. Hard to recommend one over the other although the adjuster has some advantges but nothing so critical as to make it heads above the other.

As far as tropical use, they all are fine. Anything good for cold is Ok for warm.

Bruce Bowker
Bonaire

 

[Kim]

Doesn't titanium have some issues with Oxygen if you dive Nitrox?

 

[OE2X]

There was one incident and if memory serves is was with an O2 mix at or above 70%. You are more than safe if you stay within Rec limits. I've used the titanium MK25/S600T for 2 years now and I haven't combusted once.

 

[WaterDawg]

yeah over 40%.

DAaquamaster is a bible on SP regs, maybe hell chime in. But If you plan on just doing rec dive no deeper than 130' I recomend you save the $$ and get the MK16 w/ an adjustable second stage.

 

[AdamHorsman]

On the subject of which SP regulator to get, I would recommend getting the Mark 16 diaphragm 1st stage, and any balanced second stage, the 550 is a good choice. Internally the 550 and 600 are the same, except you do not have the user adjustability of "detuning" your 2nd stage. (something you really shouldn't need to do anyways) The Mark 16 1st stage will provide more than enough air volume for you, and it's sealed. You are also able to save a couple of bucks over the Mark 25 piston first stage.

Basically, I'm of the opinion that a balanced setup is the way to go. Whether you get the 650, 600, 550, or G250, they all are balanced second stages. I would recommend staying away from the R190, and R390 "classic downstream valves" a.k.a. unbalanced second stages.

Hope that helps.

Adam

 

[divematt]

I just want to say thanks to all of the quick responses here in such a short time frame. Keep the opinions coming. I am learning so much here.

Thanks,

Matt

 

[DA Aquamaster]

The MK 2 Plus is affordable, very durable ad reliable and easy to maintain but is the lowest performing first stage SP sells with a flow rate of around 90 SCFM. It is also not balanced which means the intermediate pressure decreases as the tank pressure decreases and that means that with an unbalanced second stage like the R190 or R390, it will breathe slightly harder at the end of a dive. It is however an excellent cold water reg and is well proteced by its thermal insulating system.

The Mk 16 is marketed by Scubapro as being a medium performance first stage but it is balanced and has a flow rate of 175 SCFM which is considered high perfromance by any other standard and is more than adequate to handle any diving situation. It is balanced diaphragm design and while it is not sealed, it is well protected against cold water and makes an excellent cold water reg.

The MK 25 is a very high performance balanced piston first stage with a flow rate around 300 SCFM which is actually way more air than any diver actually needs unless they are diving very, very deep (as in below 300 ft.) The one negative comment about the Mk 25 is that despite its anti-freeze kit it does demonstrate the potential to freeze up in very cold water (below 40 degrees) if anything other than great cold water technique is used.

The Mk 25 SA is nice if you travel and are worried about weight. It is not quite as light as the discontinued MK 20 UL (Ultralight) but it is much more durable due to the use of stainless steel in critical areas.

The Mk 25T is also an excellent travel reg, but it is hideously expensive and is not the best choice for use with nitrox.

In terms of second stages the R190 and R390 are non adjustable unbalanced downstream designs. They are very reliable and are internally identical using the same poppet design and internal parts. The R390 is just smaller. There is some theoretical tradeoff with the R390 as the smaller case requires a smaller diaphragm which means less mechanical advantage to move the lever and open the poppet compared to the R190. In practice though both breathe about the same, so it is a matter of whether you want to part with more money to buy a smaller R390 that will deliver the same performance as the R190.

The S550 is externally very similar to the R390 but uses a balanced poppet design which helps it deliver the same breathing performance regardless of intermediate pressure. The balanced S-wing poppet design also allows a slightly higher flow rate making it a better choice for deep diving than the R190 or R390.

The S600 uses the same S-wing poppet assembly and same general case size as the S550 but offers an adjustment knob. This allows the diver to fine tune the inhalation effort of the regulator to mathc specific conditions during the dive and allows the reg to be tuned to lighter inhalation efforts when appropriate. The S600 does not have a great reputation in cold water as it has been noted to have a slight freeflow in very cold water. This can cause problems when it is paired with the Mk 25.

The G250 is internally identical to the S600 and both share the same poppet and adjustment features. Like the R190/R390, the major difference comes down to the G250 having a larger case and larger diaphragm. The G250 also has a much better reputation in cold water and is widely regarded as a reliable and great performing workshorse second stage. So again much like the R190/R390 the issue is one of paying more money for a smaller S600 delivering performance identical to the G250.

The X650 is still relatively new and reviews are mixed. Some divers really like it and soem don't. I personally have not been impressed with mine, but then I am pretty picky and have very high standards when it comes to regulator performance. It borrows its general shape from the discontinued D400 but applies it to a linear poppet design similar to the S-wing poppet Scubapro uses in all its other balanced second stages. The X650 however does not use the same co-axial exhaust valve/diaphragm design as the D400 so it comes up short in terms of case gemetry fault. But it has potential and I have not yet totally given up on it yet.

For most recreational divers a Mk 2 Plus R190 or R390 will serve them well. It is simple, reliable and offers good perfrormance at deoths to around 100-130 ft. Plus the light weight and compact sizes makes it a good travel reg for very little cost.

For divers who may dive a little deeper or dive in more physically demanding conditions such as strong currents the Mk 16 or Mk 25 make more sense particularly if paired with a balanced second stage. I personally like the simple bullet proof design of the Mk 25 and I like the swivel cap for the ease of hose routing that it provides. But I am not impressed with it's cold water performance. So if a diver is doing any extensive cold water diving, I think the Mk 16 makes a better choice.

With regard to second stages, I prefer the G250. Marketing types hype the benefits of smaller and lighter cases as used in the R390, S550 and S600, but with graphite/epoxy resin construction the difference in weight is negligible out of the water and the larger case displaces more water which in my opinion offsets any weight difference in the water. Jaw fatigue is often cited as being less likley with a small second stage but in reality jaw fatigue is influenced to a much greater degree by mouthpiece design and proper low pressure hose lenght.

So my overall recommendation for a do anything regulator at a reasonable price would be a Mk 16 G250. Unfortunately, Scubapro does not normally package the Mk 16 and G250 together as it does not fit their marketing strategy but it can be ordered that way by the dive shop and they should be able to get one from SP in about a week. I don't have a current price list handy, but the cost of a Mk 16 G250 would be about $40-$50 more than a Mk 16 S550 and $40-$50 less than a MK 25 G250. You lose some of the price advantage SP offers on their packaged regulators mixing and matching, but SP dealers can discount it 10% which will more than make up for that.