ScubaPro MK10 / G250 for Cave Diving
- Thread starter CaveSloth
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I suppose the old mantra: the older, the simpler, the more reliable, the better.
Which I entirely endorse!
The only "weakness" of the MK10 is thermal insulation in super-cold water, but this can be easily fixed saturating the equilibrium chamber with silicon grease and closing the holes with the SPEC boot. Which I am planning to do this month...
I used my even older MK5 under 1m of ice, and with SPEC there was no problem at all. I really do not understand why SP abandoned the SPEC system, it was just perfect for me.
Does that apply to divers, too?
Yes, of course!
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Not ideal for ice diving without a spec boot as mentioned above. The new MK25 was designed to not need a spec boot by increasing the hole size of the ambient chamber. The spec boots are nasty to deal with at service time and they can trap salt and destroy the piston if it's not done correctly, so engineering it out is ideal.
It's not as ideal for nasty water and salt water as a sealed diaphragm because you have to pay a bit more attention to cleaning them, but that's inherent to all unsealed pistons.
The newer first stages like the 25 has more flow, but you won't ever notice that.
The newest second stages are a bit smoother with lower WoB due to the case geometry, but again, you really won't notice that unless you're really paying attention and can dive them side by side.
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Unless you dive in the arctic its fine. Like 4C or below (even though SP defines cold as <10C)
They wont need to be rebuilt anymore often. The problem with sealed regs is water inevitably gets in them and does a ton of damage between servicings. Pistons are far more forgiving of the inevitable drop of water in there. If you have a mix of piston and seal diaphragm regs put the pistons on your stage and deco bottles that are shut down while diving and more likely to have water ingress. Use the sealed regs on your backgas that only would very rarely get turned off submerged.
The mk10 hasn't been made in 10+ years. If you can find them they are often a good deal used.
halocline
Contributor
I have a pair of sealed MK10s I use in caves, but the last year or so I switched to MK15s because I have heard they’re no longer supported by SP and I might as well use up my supply of seats before the world ends. When that happens I’ll go back to the MK10s.
OP
CaveSloth
Contributor
Which one is no longer supported?
MK15. The MK10 is still in wide use, so I suppose SP will continue selling service kits for several years.
halocline
Contributor
The MK10 shares a seat with the MK5, both among the most successful and popular 1st stages in history. Even if SP were to stop producing rebuild kits for them, which is extremely unlikely, there are aftermarket seats and someone else would undoubtedly get in on the manufacture of them. It's a huge market in terms of scuba parts. Considering you can easily buy these stages for well under $100 on ebay (the cost of a single service for many regs) there is no risk in buying them. The rest of the rebuild kit, other than the seat, is simply a few standard size o-rings. I have several MK5s and several MK10s, and I maintain them well. I have not purchased a SP rebuild kit in at least 5 years. I bought several seats from a dive shop and others online, I probably have 15-20 of them which should last me the rest of my diving career.
The MK15 has a unique seat and was a much less popular reg. That's why SP has stopped supporting them. I have maybe 5-6 seats for those and I might as well use them over the next 10 years. That's why I started using the MK15s as my primary cave set. I also like them very much; I think they may be my favorite of the SP balanced piston 1st stages. They hold IP forever; I've had one go well over 5 years of occasional diving with zero IP creep. But if you're looking at buying a set of SP regs, the MK15 is not the best choice unless you have a good supply of seats, which presumably you don't.
I wouldn't get too picky about the 2nd stages either. The G250, G200B, balanced/adjustable, G500, S600 are all excellent performers, nice and simple (well, the S600 is not so simple) readily available, and economical. They all work fine. I refer the balanced/adjustable for cave diving because it's metal and provides a bit of moisture on those long dives. I also use D series 2nd stages because they breathe extremely well, are totally reliable, and I have at least 15 poppets to keep the several D300s I have in service.
I just wouldn't overthink this process. It's fun to learn about the various models and variants of the older SP regs, but the bottom line is they all work great and are relatively cheap. Regulators more-or-less all do the same thing, so it's not that big a decision.
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