I know the difference but want you opinions.
Thanks for the help
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I know the difference but want you opinions.
Thanks for the help
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.
I use MK25s. Never a problem, like the hose routing.
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.
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.
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
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.
none taken.... was more referring to silt and debris getting in there than the waterQuote:
Originally Posted by Slüdge
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.
Yeah,the Mk 17, 18, 19, 20, 21, 22, 23, 24, or 25 would be good. Whatever it takes.
If I may be allowed to plagiarize a bit, "first stages with air balanced pistons deliver significantly more air to the second stage than any other first stage, while their performance is totally unaffected by the changing tank pressure. A balanced piston allows the use of lighter and more sensitive components, resulting in ultra-fast breathing response, instant delivery of air on demand, and extra high air flow, especially in low tank pressure ranges."Quote:
Originally Posted by deanme
When I started diving, the store owner was so adamant about this that he wouldn't even sell diaphragm first stages. Believe it or not, this is more important in single-tank diving than diving doubles, because there is almost no scenario where two divers will be breathing off the same first stage whereas an air-sharing episode of single-tank divers will involve two divers and one first stage. Doing this at 100' will be beyond the air-delivering capabilities of a diaphragm.
Also, I have a potential reply to your theory of not getting service every year, but I'm not sure I want to go out on that limb.
Wow, great input.
This being the case, it is not clear to me why anyone would purchase a diaphragm first stage, other then cost and cold water diving. I’m going to re-think getting replacements for my two MK25’s with the MK17’s. both my Mk25’s breath extremely well, even with low tank pressures.
Great observation about buddy breathing on a single bottle with a diaphrame. Again, assuming what you have said is correct, this seems to be a technical bit of information everyone should know to better understand the risks of diving at 100 feet with a single bottle.
I dive with an OMS H value on my single tanks. I do a lot of solo diving, and have always felt less stress diving with an H valve and two separate first stages. Also makes it easier to dive a deep wreck on doubles and then do a 60 foot reef dive the next day on a single tank with no equipment re-configuration. Lots of opportunity for fun comments by others on the boat joking about diving with two first stages and a long hose on a 60 foot reef.
Actually, I’m the one that went out on a limb saying I don’t maintain my deco first stages. I’m not interested in general “your going to die” comments. Just your technical thoughts. I’d also be interested in what components are at risk with no maintenance for an unbalanced piston. Maybe it is time to get a new set of low end OMS first stages? I’ve already signed the release forms for any advise.
But I really don’t think there are significant risks. Breathing on a deco bottle that is easily accessible and can be turned off and on for each breath in an emergency doesn’t seem like much of a risk. Maybe I’m missing something? I wouldn’t have asked if I didn’t want a polite and constructive response.
You made me do it.
I started an experiment nine years ago concerning servicing. First, on my backgas, I rebuild my regs every February, using new parts kits (as well as my open water stuff and just about everything else I have).
I have one stage regulator that I rebuild every year, but instead of a new kit, I clean and reuse all the o-rings and other parts.
I have a Mark 5 that I use for filling tires and stuff, and I have a Mark 10+ that I use with a blower nozzle for blow-drying regulator parts when I do rebuilds. Neither of these have been serviced since 1999.
I wanted to see how long this stuff would stay within specs. So far, not only the stage reg but also both non-serviced regs are spot on. :smt102
Which is not to say everybody shouldn't get their regs serviced, with new parts, every year. By the way, notice how you won't see me in the water with fewer than two regulators that have been serviced properly.
Thanks for the input. Now I realize why you were hesitant in commenting.
Like I said below, I'm going on 4 years for my deco first stages. I use them in the springs and in the ocean. I dive a lot, about 200 dives a year. All the first stages perform like new, even the deco bottle first stages, that I never service.