Scubapro mk25/s600 or Apeks XTX100??

[globaldiver]

I have use Apeks for many years (FST/TX100, DST & DS4/TX50, FSR/ATX 200) and like them alot except for the house routing with doubles (DS4). I am now switchhing to Scubapro MK25/S600 for that reason, I really like te routgin on these regs. The other teammembers dives scubapro so it also makes more sense for me to switch for that reason as well (interchangebility). Another reason that I swithch is that it is far easier to find rebuild-kits for Scubapro when travelling.

I think that they are both great regulator brands, and you cannot go wrong with either one. If I primarilly was diving in cold water, I would probabaly stick to Apeks, but Scubapro MK25 can be more freeze protected as well (filled with Christolube).

Anders

 

[mart1]

I have had the Mk-25 freeze on me in 49 degree water, twice and it was properly tuned. The XTX-200 has dove in sub 40 degree water many times withoutever freezing.

I'll bet you this was in combination with the S600. This is the problem, not the mk25 which I have been using in the coldest water combined with S550 and D400, after freezing it with S600.

mart

 

[DIR-Atlanta]

I have an older M1 (purchased in 2002 or 2003). My buddy borrowed it for a stage reg during cave 2 and had to pull it apart while entering Little River because the diaphragm somehow folded back and water was pouring into the reg. No special tools were needed to remove the inner retaining ring under water. He did this just at the entrance. The flow was pretty good that day, so it couldn't have been too hard. This reg does not have the special cave ring, whatever that really is.

I' ve had about 4-5 Atomics second stages apart for various reasons - Ti2 from ~1998, Z1 from ~2001, and at least one of the more recent vintage seconds (B2 or T2, can't remember which). They all had the threaded inner retaining ring, as well as the standard plastic outer ring. FYI, the "cave ring" is a stainless steel ring for the M1 second stage that allows the diaphragm retainer to be removed by hand. I have not seen or used one, but it sounds like it might be worth considering for a DIR rig.

It's possible that what happened with your friend was that the diaphragm got pulled far enough out so as to reduce tension on the retaining ring, making it possible to unscrew by hand. I've never been able to undo one without using some type of tool, however.

 

[1amphibian]

Does anyone have experience with hose routing on the newer APEKS 1st stage? it appears as though hose routing would be very simple for singles or doubles.

 

[Dan Gibson]

I looked at it last night and it has a notched ring. I'm guessing we just didn't tighten it down so much that it couldn't be undone by hand. Now, if that lead to the diaphragm coming unseated, maybe that cave ring is a really good idea.

I' ve had about 4-5 Atomics second stages apart for various reasons - Ti2 from ~1998, Z1 from ~2001, and at least one of the more recent vintage seconds (B2 or T2, can't remember which). They all had the threaded inner retaining ring, as well as the standard plastic outer ring. FYI, the "cave ring" is a stainless steel ring for the M1 second stage that allows the diaphragm retainer to be removed by hand. I have not seen or used one, but it sounds like it might be worth considering for a DIR rig.

It's possible that what happened with your friend was that the diaphragm got pulled far enough out so as to reduce tension on the retaining ring, making it possible to unscrew by hand. I've never been able to undo one without using some type of tool, however.

 

[DA Aquamaster]

If I primarilly was diving in cold water, I would probabaly stick to Apeks, but Scubapro MK25 can be more freeze protected as well (filled with Christolube).

Prior to the Mk 17, I used a Mk 20 equipped with the Mk 15/early Mk 20 SPEC boot and then filled the ambient chamber with Christo lube. The SPEC (Silicone Protected Environmental Chamber) system was a pain to service due to the need to remove the old silicone (very messy) but it was very effective provided that not too much silicone oozed out over time (creating space for water to accumulate and freeze in the ambient chamber). The last Spec boto produced for the late production Mk 15 and early Mk 20 was very well designed and did a good job of holding onto the silicone. It works equally as well with Christolube for divers wanting to maintain O2 clean regs.

However with it's large oval holes, the current Mk 25 does not do a good job of retaining either christolube or environmental silicone, nor does the Mk 25 work with the older MK 15/20 SPEC boots. That makes it a poor choice for filling the ambient chamber with anything.

If you are interested in doing this I do have a couple minty looking Mk 15's as well as a Mk 20 set up with these older spec boots that I would sell (since I switched to Mk 17's).

I'll bet you this was in combination with the S600. This is the problem, not the mk25 which I have been using in the coldest water combined with S550 and D400, after freezing it with S600.

In my experience the S600 does have a tendency to develop a slight freeflow in very cold water and I suspect this additional gas flow is what pushes the Mk 25 over the edge.

But...the Mk 25 still has the problem as the S600 in very cold water will not do the same thing to a Mk 17 or a similarly well protected cold water first stage.

 

[SparticleBrane]

Am I the only one with a DiveRite RG2500 set of regs on the board?
Coldest I've been with them was 50 degree water and they were fine, of course that isn't exactly "cold" for most people's definitions.

Any thoughts on these regs?

 

[Vie]

Does anyone have experience with hose routing on the newer APEKS 1st stage? it appears as though hose routing would be very simple for singles or doubles.

From my experience, hose routing wise, the FST (first stage for the TX100, ATX100, XTX100) is the best for doubles (I don't like the FST for singles but that's personal preference):

http://www.wkpp.org/images/pina_equip/regs_config_top_view.jpg
http://www.wkpp.org/images/pina_equip/regs_config_top_view2.jpg

and the FSR (first stage for ATX200, Black Pearl, Tungsten and XTX200) is nice for doubles too but is better for singles due to angle of HP ports.

 

[DIR-Atlanta]

I looked at it last night and it has a notched ring.

That's the newer design. Older Atomics (from about 2001 and earlier) have a smooth ring with a series of small holes around the edge. Either one of them can be removed by (carefully!) applying some pressure with a sharp-pointed awl. I suspect that if yours was not tightened, then that could have caused the diaphragm to pop loose, although I have seen that same thing happen with a "tight" one. In fact, that seems to be a fairly common problem with some of the Atomic second stages, and then the diaphragm can't be reseated properly without a tool.

Scubapros have a similar ring, but it's a "drop-in" - there are some tiny wing-like tabs that jut out to grab the threads and hold it in place. The worst problem with those (at least in my experience) is that they will snap off if you're not careful.

Note that I am not aware of any issues with the Atomic first stages. In fact, I have been using an Atomic "Z model" (without the swivel) as a backup on my doubles rig for several years with no problems whatsoever. The Atomic second stages are lightweight and breathe great, but I wish they'd come up with a different system for capturing the diaphragm.

 

[globaldiver]

Prior to the Mk 17, I used a Mk 20 equipped with the Mk 15/early Mk 20 SPEC boot and then filled the ambient chamber with Christo lube. The SPEC (Silicone Protected Environmental Chamber) system was a pain to service due to the need to remove the old silicone (very messy) but it was very effective provided that not too much silicone oozed out over time (creating space for water to accumulate and freeze in the ambient chamber). The last Spec boto produced for the late production Mk 15 and early Mk 20 was very well designed and did a good job of holding onto the silicone. It works equally as well with Christolube for divers wanting to maintain O2 clean regs.

However with it's large oval holes, the current Mk 25 does not do a good job of retaining either christolube or environmental silicone, nor does the Mk 25 work with the older MK 15/20 SPEC boots. That makes it a poor choice for filling the ambient chamber with anything.

If you are interested in doing this I do have a couple minty looking Mk 15's as well as a Mk 20 set up with these older spec boots that I would sell (since I switched to Mk 17's).

In my experience the S600 does have a tendency to develop a slight freeflow in very cold water and I suspect this additional gas flow is what pushes the Mk 25 over the edge.

But...the Mk 25 still has the problem as the S600 in very cold water will not do the same thing to a Mk 17 or a similarly well protected cold water first stage.

Thanks for the great offer, but I am currently not diving in waters that cold anymore...

When I will do that again I'll probably use Apeks regs instead. Meanwhile, the hose routing and interchangeability is more critical for me, hence the purchase of the mK25/s600s.

Sincerely

Anders