scubapro mk25 vs hog D1, hollis DC1 (or similar) 1st stages

[rick00001967]

so it is time to place an equip order. hopefully this week. all options researched and considered. but i am hoping some of you can maybe add last final info before making the final decision.
i currently use the Hog D1 1st stages for sidemount. love them. the hog 2nd stages as well. but they must be replaced (don't ask - long story - not relevant).
i am wonder how changing from the hog style 1st stage (same style as the hollis dci or apeks etc) with the swivel turret and 5th port on the end, to the mk 25 might change things.
i understand the mk25 also offers the swivel and the 5th port but i have never had these side by side. the mk25 seems to be a lot "longer" and not as compact. does this affect hose routing or eg position etc or should i be able to use exactly the same routing i am using now ? any info appreciated.

btw.....not interested in debating the sealed diaphragm vs piston argument but i was concerned at first about the mk25 in cold water. i since have found that they seem to perform fine. especially the new "EVO" versions. so should be no issues there. just gotta make up my mind between the s600 or g260

thx everyone

 

[bradells]

Aside from the balanced Piston/Diaphram nature ...

The MK25 is longer (don't have one in front of me, but I'd say up to an inch longer, and slightly narrower). The HP and LP ports are further apart than the D1 (due to it being a piston reg).

Here are some AL80 stages from last weeks dives with unsealed MK25



BRad

 

[karstdvr]

One thing to consider is don't get hung up on one brand. If you like the Hog D1, and have good experience with it,then keep it, and maybe consider another brand of second stage. The nice thing is so many manufacturers sell each stage separately, so chose the best of each brand to make the perfect rig. For example, for the style of sidemounting I do where my first stages can be exposed to sand/mud, as well as being bumped, I like the low profile Sherwood Oasis- dry bleed mechanism,no environmental port, and tough as nails. But, I hate their second stages, so I use Scubapro G250 or Dive Rite unbalanced. I say be eclectic, and choose the best of each company.

 

[rick00001967]

don't get hung up on one brand. If you like the Hog D1, and have good experience with it,then keep it, and maybe consider another brand of second stage.

as i said, long story, not relevant. short(ish) version.....i have to switch to hollis or scubapro cuz thats what our shop sells and we are putting together our first sm program. we need some new regs for that. we are also replacing our main rental reg stock. so the hogs are out. i got my hands on a hollis dc1 / 212 and feel the 212 second stage is not robust enough to be used in rentals and with students etc. we will most likely be going with scubapro. and the mk25 seems to be the best option for a 1st stage in sm. since i use hog d1's currently i am only curious about the possible differences between that style of 1st stage compared to the mk25.
but i understand your point. thx for posting
rick

 

[kensuf]

Unbalanced second stages can be problematic if you dive some environmentally sealed diaphragm first stages deep. If you dive really really deep (like stupid deep) on the environmentally sealed first stages, you may also experience problems with LP hoses. Basically the intermediate pressure of those first stages goes up by roughly 0.2bar per ATA of depth, at 10 ATA your intermediate pressure has gone up by almost 30 psi. Some reg manufacturers, who otherwise make great gear (Apeks), are marketing this problem as "overbalancing".

I like the ScubaPro balanced piston design. I've got on old MK5 that I've owned since 1981 that still works like a champ.

I also like diaphragm first stages, I've just taken to removing the environmental seal and cap on them after experiencing a nasty free-flow from an unbalanced second stage at 270'. I have a friend that had the over-pressure relief valve on his O2 feed for his rebreather freeflow at 300' due to the same problem.

 

[karstdvr]

Unbalanced second stages can be problematic if you dive some environmentally sealed diaphragm first stages deep. If you dive really really deep (like stupid deep) on the environmentally sealed first stages, you may also experience problems with LP hoses. Basically the intermediate pressure of those first stages goes up by roughly 0.2bar per ATA of depth, at 10 ATA your intermediate pressure has gone up by almost 30 psi. Some reg manufacturers, who otherwise make great gear (Apeks), are marketing this problem as "overbalancing".

I like the ScubaPro balanced piston design. I've got on old MK5 that I've owned since 1981 that still works like a champ.

I also like diaphragm first stages, I've just taken to removing the environmental seal and cap on them after experiencing a nasty free-flow from an unbalanced second stage at 270'. I have a friend that had the over-pressure relief valve on his O2 feed for his rebreather freeflow at 300' due to the same problem.

Interesting you've had problems with unbalanced 2nd stages. There was a brand of Dive Rite second stages a few years that breathed stupid good (actually better than Scubapro) that is unbalanced. I snatched up a few of them with rebuilds, and to this day they are one of my favorite, although I think the deepest I have took them was 180ft. Ironically the balanced cousin to that reg breathed fairly poor.

I agree with the MK5 you mentioned,but I was always a MK10 fan. Do you remember the experiement that Tyler Moon, Ted Cole, and Steve Berman did on a Mk10 versus a Mk20? Mk10 whipped the Mk20 was the end result.

 

[shoredivr]

I've had those little holes in the MK25 body pick up grit and silt in a River sidemount dive and start bubbling.

never had any problems like that with DiveRite sealed first stages. I like how they breathe and function in cold water. The only slight drawback for sidemounting was the lack of a fifth port on top of the turret. Well DiveRite has come out with a new first stage that has a fifth port. Check those out.

---------- Post added January 10th, 2016 at 01:53 PM ----------

SCUBA Diving Equipment for Technical, Sidemount, Rebreather, Wreck and Cave Diving: Dive Rite, Inc - Product Catalog - XT1 Regulator

 

[rick00001967]

as much as i appreciate any interest and input....can we pls stick to the question at hand. perhaps i should simplify.

i now use hog D1 1st stages. i will be using scubapro mk25 1st stages. i have no choice in the matter. what differences might i expect with respect to hose routing, reg position, etc etc if any ?

i suspect there will be little difference but it would be nice to hear from anyone who has used both these in sm

thx everyone

 

[kensuf]

Interesting you've had problems with unbalanced 2nd stages. There was a brand of Dive Rite second stages a few years that breathed stupid good (actually better than Scubapro) that is unbalanced. I snatched up a few of them with rebuilds, and to this day they are one of my favorite, although I think the deepest I have took them was 180ft. Ironically the balanced cousin to that reg breathed fairly poor.

I agree with the MK5 you mentioned,but I was always a MK10 fan. Do you remember the experiement that Tyler Moon, Ted Cole, and Steve Berman did on a Mk10 versus a Mk20? Mk10 whipped the Mk20 was the end result.

The problem with the unbalanced second stage only appeared when mated with an environmentally sealed first stage that was taken to depth. I first noticed a small amount of bubbling about 220', but it really started to free-flow when we hit 270'. About a year ago Beckner had to abort a dive in Twin Dee's because the OPV for the oxygen reg on his Meg started burping at 320'.

Both problems were caused by the intermediate pressure creep from the overbalancing "feature" of the first stage. At 260fsw, the intermediate pressure on an overbalanced environmentally sealed first stage has gone up by 20psi. The problems from this could be resolved by either de-tuning the second stage more, cranking down the OPV more, or removing the environmental cap. Personally, I chose to remove the environmental cap on my regs.

A lot of people have strong opinions on Mark, but this article on his web-site explains the problem in-depth. deep diving regulators

BTW I wish I could find some MK10's cheap. It's still easy to find the DIN conversion kits for them.

 

[bamafan]

I dive the Mk25 on my sidemount tanks and find they route extremely well. I haven't had any problems with them or my mk20's or mk10's. I don't dive cold water as I live in Florida. The coldest I see is 50 degrees in the rivers this time of year.