Mk25 Scubapro

[drdaddy]

I came here looking for advice on regulators and when I said I was going to get a Mk25 1st for diving before this spring 2009 I was told that would be a poor choice due to local water temps and free flows trouble. The advice here was contray to all my real world diving experience with people using this 1st stage and I am happy to continue to report they remain wrong.


WRONG

Yep that is right, outside of extreme cold like diving under the ice on a fresh water lake or the ice at antartica the Mk25 1st stage is great in "cold water" and tested with 4300 psi at 2C without trouble. That is right, it is the required performance level for the regulator, your cold water reg might not make that.

Anyone that says a Mk25 Scubapro 1st stage has trouble with cold water below 50 F is incorrect. They don't know what they are talking about and my experience and dive log says different.

People on this forum claiming expert status Protray the Mk25 1st stage as a poor choice and they are completely wrong. And when I say this I do so with such previous orgainsations linked to as the United States Navy indicating that not only is the Mk25 good cold, they approve it.

Belce,

You sound a little defensive. It looks like others are agreeing with you that they also have found the MK25 to be a fine regulator and that it works well in the cold.

But it's like my older Sherwood Oasis. I've never had any problems with it in tropical, deep, or a number of cold water dives (Clear Lake 40 +-5* degrees Fahrenheit). My Sherwood and your ScubaPro are great bulletproof regulators. However, if we were to dive (more) exclusively in colder water (especially when the surface was inaccessible) , there probably would be a better choice.

Oh, by the way. I also find some of the BPs and drysuit folks can be a bit overbearing , but I listen and learn.

In the meantime, dive, learn, and enjoy.

 

[halocline]

.....it is my understanding that some of the older SP piston regs did offer a SPEC kit similiar to the little rubber band/Christolube combo Atomic uses

Yes, this is true, but you don't need the rubber band to pack the ambient chamber. The later MK5s had very small holes specifically to keep the silicone grease from oozing out too much.

SP eventually went with the "TIS" system that's basically anti-ice coatings and bushings. But, I don't see why you couldn't still pack the ambient chamber. The MK25 holes are big, so more grease would leak out, but Christolube is pretty stiff grease so it would probably work fine.

I'm looking for two MK10 SPEC boots if anyone has them for sale.

 

[akscubaduck1]

It's true the older MK 25s did freeze up. The new MK25af has for the most part cured that problem. With almost all the metal parts insulated from each other, a teflon coated main spring, and the ribs on the cap, this reg has worked well for me in 34 degree water. Alaska
And hey Mattboy I might have to MK10 SPEC boots if you want them.
Pulled them off two MK10s that were destroyed because of the boots and lack of regular service (mainly lack of service).
I'll get back to you.

 

[Belce]

I am not nor have I been defensive, when I said folks were wrong to suggest the Mk25 was not good in cooler than temperate water it was a challenge.

These folks contradicte my experience and those of the people I know and I would like to see more than "oh piston, free flow".

Their assessment is wrong and I am sure that people that refer to this forum would like to see correct info, instead of posters old wives tales.

 

[rstofer]

It's pretty hard to prove a negative. The fact that YOU haven't had a free-flow with YOUR regulator on YOUR dives doesn't mean that it can't or won't happen. Nor does it suddenly make a technology universally recognized as somewhat deficient for cold water a satisfactory approach.

Folks have actually experience free flows in cold water with Mk 25s. That's the reason the wive's tale exists. It has happened.

If we assume that Oceanic knows anything about regulators, we should also pay heed to the fact that their Owner's Manual clearly states that NONE of their piston first stages are to be used below 50 deg F. Now, I realize that there is a difference between SP and Oceanic regs but I think it is more in the label than in the mechanics.

If you wander over to the AquaLung site, they mark their cold water regulators with a snowflake icon. I believe that every one of their cold water regs is based on a diaphragm first stage.

I didn't do any more than just glance at the site so I don't know anything specific about their regs.

But the thing is, there have been free flows with Mk25s. This isn't a problem unless you run out of air before you can resurface but why recommend that someone even take the chance when, for the same money, they can get a regulator that is actually built for cold water?

Or better yet, buy the Oceanic Delta4/FDX10.

Richard

 

[Packhorse]

I am not nor have I been defensive, when I said folks were wrong to suggest the Mk25 was not good in cooler than temperate water it was a challenge.

These folks contradicte my experience and those of the people I know and I would like to see more than "oh piston, free flow".

Their assessment is wrong and I am sure that people that refer to this forum would like to see correct info, instead of posters old wives tales.

Yes and your comments contradict other peoples experience. So who is right?
The people who say a MK25 can free flow in cold water because it happened to them ?
Or the people who say a MK25 will not free flow in cold water because it hasnt happened to them (yet)?

Sorry dude but your logic is flawed.

 

[4sak3n]

I am not nor have I been defensive, when I said folks were wrong to suggest the Mk25 was not good in cooler than temperate water it was a challenge.

These folks contradicte my experience and those of the people I know and I would like to see more than "oh piston, free flow".

Their assessment is wrong and I am sure that people that refer to this forum would like to see correct info, instead of posters old wives tales.

Do yourself a favour and do a quick Google search on the Popperian philosophy of science. Like all philosophies it has some gaping holes in it but it does espouse one of the most fundamental core axioms of science: lack of data (never having had a freeflow) can never prove something, only indicate that it hasn't been disproven yet.

 

[JohnB47]

I used to dive under ice in quarries in Ohio and Indiana with a MK5. The MK25 is supposed to be better than the MK5 for cold water diving.

...John

 

[lowridersvt]

Well responding to this seems like a waste of time but i, bored so why not.

Mk25 is a good reg in my experiance with free flows with these first stages its usaly a second stage failure from those garbage plastic air tubs ie.S600/g250hp. Had many free flows even with my mk14 and mk17. But mk25's become much better with a good second stage ie. old g250 or g250v with the metal air tube. I know tones of guys that ice dive and dive super cold water with mk25's and mk20's with no major issue but you have to have some type of procedure. Most guys say with those regs once there down they have to stay down.

I have many dive in the 32-35deg range with air temps in -25to-35deg with piston regs mostly atomic m1's with no free flows but every reg will freeze .

 

[rstofer]

The Challenger disaster was caused by an o-ring failure. NASA management convinced themselves that all evidence of partial failure during previous flights was not as important as the fact that the o-ring hadn't failed YET. Therefore, by their convoluted logic, o-ring failure was not a concern.

All flights had the problem, none failed until the Challenger.

Why do NASA engineers figure the catastrophic event probability at 1:100 while management says it is 1:10,000? That's a pretty huge disconnect.

The same convoluted logic is being applied here. There is anecdotal evidence to suggest that piston designs are a poor choice and there are regulator designs known for superior cold water performance. Why make the wrong choice?

BTW, the US Coast Guard, US Navy and NOAA have selected the Oceanic Delta 4/FDX10 as their cold water regulator of choice. They did the joint selection process after the Coast Guard lost a couple of divers in cold water. No, I don't know what regulator they were using. But I know what they are using now!

Richard