XTX FST, MK17 or DS4 for twins

[Adobo]

Thanks for the G250 summary DA.

Our 5yo G250 definately has a higher cracking effort than the similar vintage S600. I'm not sure if that's a consequence of tuning or what. But my wife actually uses it as a backup cause she prefers the S600 in her mouth. I would consdier the G250V nowadays although the S600 seems to be more common around here in shops.

I have a super old G200b (same thing as a g250 minus the adjustment knob), a G250HP and on regular occasion, breathe from s600s (S-drills). They all feel pretty different to me. I suspect most of it is due to tuning.

 

[xiSkiGuy]

I have almost all of the regs in question. I own MK25/S600s, Mk17/S600s, XTX50/DS4s, and XTX200/FSRs. They are all great regs with only minor issues of preference differentiating them. The MK25/S600s are probably in the best "tune" right now for breathing performance. However, like DA I prefer the "cleaner" hose routing of diaphragm 1sts to the routing on balanced piston 1sts. That being the case and IMHO, the XTX200/FSRs have the best combo of hose routing and breathing performance. I use them the most often. The Mk17 breathes well, but I don't really like the position/angle of the HP port. The DS4's hose routing is OK, but despite very similar internals to the FSR, I can't quite get it to breathe as well.

 

[rjack321]

I guess we all have different definitions of "clean" hose routing I have been very pleased with the Mk10/20/25 swivel turret style with bottom port.

 

[Jason B]

I use Apeks DS4's and ATX/XTX50's on everything. Good hose routing (on backgas and deco/stage bottles), good breathing, tough as nails, simple design, easy to get rebuild kits for.

 

[RTodd]

Personally, I prefer APEX because they simply deal with abuse and keep functioning longer. Having said that, I have had a few apex that were produced a few years ago during the manufacturing shift that leaked/ failed so badly I just threw away the first stages. Apex overhaul kits are about $10, SP is 3.5 to 4x as much. I dive with plenty of SPs too because I prefer pistons for stages. The hose routing on the SPs as back gas is easier to make clean but I prefer the actual routing from the DS4s.

Some parts of the world, such as Mexico where Apex parts are difficult to come by, dictate which reg is the best choice.

The flow rates are overkill already, ignore that. SP has slightly better ease of breathing, but are also slightly more prone to freeflow. On a long dive I am going to be breathing SP stages but have back gas regs I don't have to worry about freeflowing as much. On a shorter dive, the slight increase in WOB, and it is slight, isn't really noticeable.

I use APEX for single tank OW stuff because they last longer between overhauls.

 

[fweber]

Another user of DS4's here. Can't comment on how their hose routing compares with the MK17's. Definately prefer it to that of one of my buddy's MK25's. They both work however.

I would go with FSR's or TEK3's if it weren't for the cost. Just can't justify the additional expense when DS4's function just fine.

 

[LG Diver]

I guess we all have different definitions of "clean" hose routing I have been very pleased with the Mk10/20/25 swivel turret style with bottom port.

I think you can get a "clean" hose routing with diaphragm 1st stages but you can't get a hose routing that doesn't put some serious bends in the hoses. (see my Mk25 hose routing below).

When I bought my SP regs I debated between the S600 and G250HP, and I finally landed on the S600's because SP now offers a package with a Mk25/S600 but not a Mk25/G250HP so it would have been more expensive to go with the latter. Also, a minor point that the LDS owner pointed out is that some folks that scooter a lot (not me right now) have observed that a G250HP as a backup reg tends to be more prone to freeflowing while scootering than a S600 because it has a larger faceplate and the flow of water can push on it. I can't personally speak to this issue at all, so take it for what it's worth.

As far as the old Apeks vs SP: I have an ATX200 reg for my single tank diving, and I notice a significant difference in WOB and a quantifiable difference in SAC rate between it and the SP.

 

[DA Aquamaster]

I have a super old G200b (same thing as a g250 minus the adjustment knob),

G200's and G200B's often show up on e-bay in near mint condition. When they do, I buty them and install G250 Air barrels - which creates a G250 as other than the purge cover design and the air barrel they are identical.

 

[Adobo]

Okay.. Show and tell time.

Here is a pic of my mk17s.

and a closeup:

I have also tried having the first stages rotated about 180degrees. However, in that setup, the first stages were preventing me from pinning my head against the manifold (which in turn restricted my ability to see directly ahead of me).

Since I have a donut wing, I have also been playing with the hose routing. In this variation, I tucked the wing between the tanks and the hoses that come from the left post. This provides a little extra reach for my backup regulator.

 

[coldsmoke]

You might take a look at these:
Salvo Supply - Salvo SR2 First Stage

I don't know anyone who uses them, so I can't say anything for performance. I dive mostly cold water so I prefer sealed diaphram regs and this is the only one that I have seen that has a bottom lp port. Seems like it would be the best of the sp and apeks - assuming performance is similar.

I don't know if you can get them serviced where you live but service kits are readily available if you are into servicing your own.

Hunter