MK 25 or MK 17 for Cave Diving

[Blackchains]

I know the difference but want you opinions.

Thanks for the help

[swcapitalo]

while the mk25 is a REALLY nice reg i prefer the sealed mk17. its a little extra piece of mind for me knowing that nothings getting in there.

[BobK]

I use MK25s. Never a problem, like the hose routing.

[Sludge]

With all due respect, if you're not diving in very cold water, there's absolutely no benefit to a sealed reg. The only place "water gets into the reg" is the ambient chamber. It's a non-issue.

Here's my official advice, worth exactly what you paid for it (although I've been a certified technician for over twelve years, trained by most of the major manufacturers): if you're diving in water below 40°F, buy a Mark 17. If the water isn't that cold, get a Mark 25.

Or any of the Atomics, except for the T-2, which for some ridiculous reason, only comes sealed.

[flyczek]

I have the older Mk16s which I have been diving several years with no complaints. They breathe well and the way the ports are arranged worked really well for hose routing in backmount and now works great for sidemount. Works good, lasts a long time.

For salt water I use piston regs though. My reasoning is that they are easier and cheaper to service. If you are not servicing regs yourself, this may not matter to you.

[DogDiver]

I have 5 MK 20's that have been upgraded over ther years. Been using them without failure for almost 10 years now. (6 month service of course) I trust them for myself as well as my cave diving son and daughter...nuff said.....Ken

[Walter Pickel]

We use MK25s/S600s almost exclusively (back mount, stages, deco). I do have a few Atomics M1s I use for sidemounting. They were given to me so I use them.

[swcapitalo]

With all due respect, if you're not diving in very cold water, there's absolutely no benefit to a sealed reg. The only place "water gets into the reg" is the ambient chamber. It's a non-issue.

Here's my official advice, worth exactly what you paid for it (although I've been a certified technician for over twelve years, trained by most of the major manufacturers): if you're diving in water below 40°F, buy a Mark 17. If the water isn't that cold, get a Mark 25.

Or any of the Atomics, except for the T-2, which for some ridiculous reason, only comes sealed.

none taken.... was more referring to silt and debris getting in there than the water

[deanme]

Sludge,

Can I ask, why do you prefer the piston over the diaphragm for water above 40? This is to say, for diving in 72 degrees at Ginnie, or for diving in 85 degrees in Pompano, why would you prefer the MK25? I would value your input because of your 20 years of experience servicing different units.

I have been diving MK25’s for 11 years with no problems, but I know some prefer a diaphragm. I’m thinking about giving my two older MK25’s to my new wife who is just starting out diving, and thought about getting two MK17’s to replace them. I dive exclusively in the Florida springs and warm ocean water, so cold water diving (below 50 degrees) is not an issue.

I also have another question for you if I could. I have three low end OMS first stages (R 1 Stage – P) I use for deco bottles. These are unbalanced Piston units that I think are fairly simple in design. Although I have my MK25’s serviced yearly, I have never had these low end OMS units serviced. They only cost me $160, including a low end OMS second stage (R242). It is difficult for me to spend $40 to service a unit that only costs $80 new. I will soak them in vinegar occasionally for 20 minutes, but that is all I have ever done to them, and they still breath well.

My logic, flawed as it may be, is that if there is a problem with the first stage on a deco bottle, I can always turn the tank on, take a breath, and turn the tank off. I’ve been diving these units on my deco bottles for 4 years now, with no problems. I realize I’m taking a risk. I’m interested in learning from you for specific technical comments about the risks I’m taking, and what your thoughts are.

For my high end second stage, I use S600 which I have serviced yearly. For all my other second stages, I recently purchased a bunch of last year’s Salvo second stage for $80 each. Breaths pretty well and is fairly rugged.

[aw]

Yeah,the Mk 17, 18, 19, 20, 21, 22, 23, 24, or 25 would be good. Whatever it takes.