Mk25/G250 or Mk17/S600 for Tec applications?

[College Diver]

My shop will be placing our opening order within the next few weeks for ScubaPro, and I am seriously thinking about upgrading the regulators I am currently using.
I was rolling around the idea of going with the Mk25/G250 set-up, or possibly the Mk17/S600.

What are people using out there, and what are the pros/cons of each?

[Grateful Diver]

I use MK25/S600's on my tech rig ... was originally using Apeks DS4/ATX200's but decided I liked the routing on the MK25's better, and liked the breathing on the S600's better ...

... Bob (Grateful Diver)

[David P]

Mk25 does have better hose routing, Mk17 is sealed...I'd probably opt for the Mk17

[Ben V]

I second Bob's vote...

The majority of Mo Cal doubles guys are using MK 25's much much easier routing than the DS4's I'm using right now... If I could get a good deal on them I would go for MK 35's

[dsteding]

MK 35's

MK35s?

[LCF]

I've heard rumors over and over again that the Mk25 isn't a good cold water reg (given to freeze-up) but I've used mine in water down to 43 degrees without problems.

I have MK25/S600s and I LOVE them. I haven't breathed off a G250, though.

[CompuDude]

For hose routing reasons, I'd go with the MK25. Both 2nd's you mention breath well. I use the MK25/S600 combo myself (with S555 secondary to save a few bucks... same reg just not adjustable).

Given that you mostly dive Monterey (at the northern limit) and farther south (mostly), from what I recall of our convo, there's no reason to avoid the MK25 (based on any temperature concerns).

[rjack]

I've heard rumors over and over again that the Mk25 isn't a good cold water reg (given to freeze-up) but I've used mine in water down to 43 degrees without problems.

I have MK25/S600s and I LOVE them. I haven't breathed off a G250, though.

Where were you diving 43F water? Maybe a lens of colder water on the surface in winter? At depth, if you are seeing <47-48F in Puget Sound/Strait of Georgia your gauge sensor is screwy. At depth where the volume of expanding gas is much greater (and hence adiabatoc cooling is greater) is where temp counts.

Cold for the purposes of icing/freeze up is less than about 40F. DIE (tony) can probably offer some Great Lakes insight there.

I have mk20/25s and love them. That said I would like to try ice diving sometime and I will convert my DR deco regs or borrow some sealed regs for that.

[amascuba]

The MK25's do fine in cold water. Here's a picture of some of guys diving in colorado.

[kevfin]

Good question. Thanks, kind of wondering about this myself.

I thought the other issue between the Mk17 and the Mk25 was that the Mk17 can be adjusted to a higher IP if needed. Is that true, a real issue, or concern?

Also, I'm looking at the DS4/XTX50 or the Mk17/S600 for my doubles... kind of torn, keep going back and forth.

[Ben V]

MK35s?

uhm Typo dude

[amascuba]

Good question. Thanks, kind of wondering about this myself.

I thought the other issue between the Mk17 and the Mk25 was that the Mk17 can be adjusted to a higher IP if needed. Is that true, a real issue, or concern?

Also, I'm looking at the DS4/XTX50 or the Mk17/S600 for my doubles... kind of torn, keep going back and forth.

MK17's are balanced diaphragms and MK25's are balanced piston regulators.

balanced diaphragm regulators have an external IP adjustment... and honestly should be checked from time to time because the diaphragm is just a little rubber seat.

The piston regulators that I've worked on have little washer seats that can be slid over the pistons rod. You can add/remove these washers to lower or up the IP pressure, but for the most part you really don't need to mess with that on piston regulators since the pistons don't deteriorate and change over time. They are mostly made up of a piston, spring, hp seat, and a few o-rings.... very simple and very reliable.

[Vie]

I was rolling around the idea of going with the Mk25/G250 set-up, or possibly the Mk17/S600.

What kind of G250 are we talking about here? G250, G250HP or G250V ?

I agree with most that the MK25 would offer the best hose routing. However if cost is a concern I would opt for a MK17/G250HP combo (the hose routing, while not as nice as with the MK25, is not bad).

[LCF]

Well, my computer said the water in Nanaimo last January was 43 degrees, and given the ice on the surface, I was willing to believe it. And I had a couple of dives this winter where it said 43, but this is a different computer and I think it reads a couple of degrees low, maybe.

[John_B]

Does anyone know anything about the MK19? It was supposed to be a sealed diaphragm like the MK17 but with the turret like the MK25. DiveInn seems to be selling them from Spain (examples here and here) but they don't seem to be available anywhere else.