Scubapro mk25/s600 or Apeks XTX100??

[Tanked Monkey]

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

Awesome post! I was on the fence for first stages for my new doubles with the FST vs. the DS4. The DS4 has the price advantage, but the FST has the breathing advantage. Because of the breathing advantage, I wanted to go with the FST, but was unsure how the hose routing would go (I don't know anyone who dives doubles with FST's). I have been searching for a while trying to figure out the hose routing, but didn't find those links. Thanks for posting them!

Best,
Mike

 

[Vie]

Awesome post! I was on the fence for first stages for my new doubles with the FST vs. the DS4. The DS4 has the price advantage, but the FST has the breathing advantage. Because of the breathing advantage, I wanted to go with the FST, but was unsure how the hose routing would go (I don't know anyone who dives doubles with FST's). I have been searching for a while trying to figure out the hose routing, but didn't find those links. Thanks for posting them!

Best,
Mike

I posted the reply because the original question referred to "newer" Apeks first stages (admittedly the FST in it's TX100/Zeagle days is not new). I use FSTs when diving doubles - however I think the DS4 is more than good enough for back gas; I personally don't like the DS4 hose routing when used with AL80 doubles (I don't dive with steel tanks) but the routing is fine for steel tanks. I can't "prove" it but the "real world" breathing performance of the DS4 and FST is probably rather similar in "feel" and I doubt I can tell the difference.

 

[Tanked Monkey]

They're packaging the "new" FST (w/o the 1/2" port) with the new XTX100's, which is what Chris was asking about. Thanks again for the hose routing pics (it clears up a few questions I had).

Mike

 

[Vie]

No probs, Mike.

I'm looking for pictures of hose routing (doubles) for Scubapro MK17s, if anyone has them...

 

[Dan Gibson]

Well the first stages should be good since the guys who designed it used to work for SP. I find them a little easier to work on then the older MK10 because you don't have to dig out the piston stem o-ring. So far the only drawbacks I see (other than the 2nd stage diaphragm design) is the cost to service these things and the initial price. The mouth pieces that come on the M1 are the best IMO. Very comfortable. I have a set of Z1s as backup for doubles as well.

I hear you on those tiny wing tabs on the SPs.

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.

 

[Amphibiman]

Apeks all the way !!

 

[1amphibian]

Thanks for the pics of the hose routing, clears a few things up for a few of us apparently.

 

[spcoun]

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.

Then again I keep it tuned correctly. I don't allow it to free flow.

The MK-25 froze during a dive, while in my mouth and there wasn't much that could be done with it except retire it and give it to someone who only dives warm.

Was that in monterey? May 19th my computer said 48 degrees. No problems with an atx 200 either. :light:

 

[ScubaGypsy]

I'm curious about the reports concerning the Mk25/S600 in cold water. I have used this regulator throughout the past two winters in New England with water temperatures in the upper 30's/low 40's without any problems. I have the Mk25AF but don't know if that is the reason. Conversely I have a G250 for my secondary and had some free flow issues though since my last tune-up it seems to be working fine as well.

 

[DA Aquamaster]

There really is no "AF" model as all Mk 25's have the AF kit installed. Although how extensive this kit is, depends on the age of the Mk 25. All Mk 25's produced since about July 2003 have the full "AF" treatment and any Mk 25 with a current annual service will have most of the full "AF" kit.

What early Mk 25's won't have is the latest piston or finned swivel cap, but they can be upgraded. The latest piston used in the AF kit is basically he same composite piston ued in the earlier MK 25 but with a mirror polished piston stem. The part has adealer cost of about $21.00. The finned swivel cap an also be retrofitted adn the dealer cost on the part is again about $20-25. But to get it to look right, you need the latest LP port swivel which doubles the cost. In my opinion it really is not worth either upgrade.

Cold water success with the Mk 25 varies. Some people have good luck with them and other people do not. Given that not every cold water diver has perfect technique, I don't recommend it to anyone for cold water diving. The Mk 17 is a much better choice for very cold water diving as it is fully sealed and very reliable.