In between the two first stages mentioned, which would have the upper hand? Even though the MK 25 is the flagship the MK 17 seems like its got the total package w/out the swivel and one more low pressure port. If I understand correctly to get the anti-freeze upgrade kit it'll cost a good chunk of change. While the 17 is already a closed diaphram and already has the anti-freeze wouldn't IT be considered the top dog rather than the 25? I mean why spend an extra $50.00~$60.00 for a upgrade kit for the flagship while the middle class already has it for a reasonable price?
MK 17 vs. MK 25 First stages only.
- Thread starter triton013
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Soggy
Contributor
Where are you diving? The environment will help determine your needs. I dive with a Mk25/S600 on my single tank reg and it breathes amazingly, but freezes easily because it is exposed to the water. My doubles are Apeks, though as I believe they are more reliable in cold water.
IMO, ScubaPro is a piston reg company. Most of their regulators are pistons and that's what they are good at. If you want a diaphragm reg, I'd look at Apeks instead. IIRC, the Mk17 is fairly complicated inside, at least relative to other diaphragm regs out there.
IMO, ScubaPro is a piston reg company. Most of their regulators are pistons and that's what they are good at. If you want a diaphragm reg, I'd look at Apeks instead. IIRC, the Mk17 is fairly complicated inside, at least relative to other diaphragm regs out there.
I agree with you that the Mk 17 has a legitimate claim to being SP's top of the line first stage. I have noted that some Eurpoean sites also market it much more aggressively than the Mk 25, so it's status appears to be changing outside the US.
Some older Mk 25's (made prior to July 2003) do not have the full upgrade kit and may benefit from a new piston and, to a much lesser extent, the finned swivel cap. But there should be no charge for the "AF" kit on a new Mk 25 as it is standard on all models and they come that way from the factory.
The Mk 25 has been known to suffer from freeze flows in water colder than 45 degrees while the Mk 17 has been well designed and tested and is basically bullet proof in cold water.
It's true that SP has made very good balanced piston regs since the mid 60's, but that does not imply an inability to design and build an excellent balanced diaphragm reg. The Mk 17 is based on the Mk 16/Mk 18 design but with improvements such as an new seat alignment system, a dry sealed ambient chamber, and a much more effective means to balance the seat carrier. SP spent 3 years developing the Mk 17 as a state of the art blanced diaphragm design and they have succeeded in that goal.
As for it being more complicated than other balanced diaphragm regs, that's a very misleading statement. It does use a separate passage to route air to the back side of the balance chamber (rather than relying on air slipping past a pin through a hole in the seat as in other balanced diaphragm designs) and this larger passage does improve response time compared to traditional balanced diaphragm regs. It does involve more machining inside the reg, but it does not increase the parts count. In terms of moving parts, it is as dirt simple as any other environmentally sealed balanced diaphragm reg.
In cold water testing, the Mk 17 survived high flow rates at 165 ft for 200 minutes (the end of the test) in 35 degree water and no other reg tested (Aqualung, Apeks, etc) can make that claim.
Personally, I replaced my Mk 25's with the Mk 17 shortly after it was introduced and have had zero problems with it, including a large number of deep dives in 33-40 degree water.
The shop I work for is also an Aqualung/Apeks dealer, but I'd recommend the Mk 17 over any other first stage available today.
Some older Mk 25's (made prior to July 2003) do not have the full upgrade kit and may benefit from a new piston and, to a much lesser extent, the finned swivel cap. But there should be no charge for the "AF" kit on a new Mk 25 as it is standard on all models and they come that way from the factory.
The Mk 25 has been known to suffer from freeze flows in water colder than 45 degrees while the Mk 17 has been well designed and tested and is basically bullet proof in cold water.
It's true that SP has made very good balanced piston regs since the mid 60's, but that does not imply an inability to design and build an excellent balanced diaphragm reg. The Mk 17 is based on the Mk 16/Mk 18 design but with improvements such as an new seat alignment system, a dry sealed ambient chamber, and a much more effective means to balance the seat carrier. SP spent 3 years developing the Mk 17 as a state of the art blanced diaphragm design and they have succeeded in that goal.
As for it being more complicated than other balanced diaphragm regs, that's a very misleading statement. It does use a separate passage to route air to the back side of the balance chamber (rather than relying on air slipping past a pin through a hole in the seat as in other balanced diaphragm designs) and this larger passage does improve response time compared to traditional balanced diaphragm regs. It does involve more machining inside the reg, but it does not increase the parts count. In terms of moving parts, it is as dirt simple as any other environmentally sealed balanced diaphragm reg.
In cold water testing, the Mk 17 survived high flow rates at 165 ft for 200 minutes (the end of the test) in 35 degree water and no other reg tested (Aqualung, Apeks, etc) can make that claim.
Personally, I replaced my Mk 25's with the Mk 17 shortly after it was introduced and have had zero problems with it, including a large number of deep dives in 33-40 degree water.
The shop I work for is also an Aqualung/Apeks dealer, but I'd recommend the Mk 17 over any other first stage available today.
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