MK25/S600 OK for Ice Diving?

[tplyons]

Hi all,

When I bought my regs, I had no intention of using them for ice diving so I opted out of the MK17 which is a much better cold water reg.

Long story short, a few guys from my shop had a crazy idea of doing some ice diving this winter (and getting our ice diving certifications) but here's the question... will I be ok with my MK25/S600?

My SAC rate is a bit higher than I'd like it, around .80 CF/Min.

I believe there are a total of three dives involved over two days. I'll be wearing a drysuit so there's some more added strain on the MK25.

Thoughts?

 

[exposure]

It seems that this reg is not excellent for ice diving. If you still have your manual, you should check the limitation.
And if any doubt, you should better rent one for 3 dives and enjoy these 3 dives

 

[buddhasummer]

Not saying it couldn't be done but this regulator is not suited for ice diving, you should consider a sealed 1st stage such as the MK17.

 

[elan]

You can do ice diving with this reg and I know people who do it regulary but.. You have to have solid cold cold water skills. If the air temp is below 0c your setup should be in either in your warm car or in the water. Never in the cold air except when you carry it from the car to the hole. If you submerge mk25 and then keep in on air you are screwed it will freeze and frer flow. If you have the new metal barrel s600 you should be fine underwater. If its the plastic one it will be more finicky.
Overall its doable but can be tricky. If you do repetitive dive leave the tanks in the water and never take it out. If you have to switch the tanks you can forget about it as as soon as they leave water they will freeze.
A diaphragm reg is definitely better for the job.

 

[tplyons]

Thanks guys. I'll see what I can do about getting my mitts on a MK17 for the trip.

Does anyone out there rent first stages?

 

[halocline]

I'm by no means an experienced ice diver, but I can read and the MK25/S600 combo has a very mixed reputation in cold water. You might try switching the 2nd stage for an all-metal 109 converted to balanced/adjustable. It would certainly be a cheaper option than a MK17, and from what I've read, the 2nd stage does seem to make a fairly significant difference in the MK25's cold water reliability.

Another inexpensive option would be to find a SPEC equipped MK10, and pack the chamber with grease. SP should have maintained this system through the MK25....like atomic has done.

But the easy solution is to buy a MK17, which any SP dealer can sell by itself. It might be pricey, though....

 

[Fishpie]

The Sub Gear SG-1000, Halcyon H-50D and the TUSA RS-790 1st stages are rebadged Scubapro MK17's.........apart from the Halcyon not sure if you can buy just the 1st stage.
Apeks, Zeagle, Aqualung, HOG also make great cold water regs.
Don't forget that a budget Sherwood will also do the job very well.
........if you were really on a budget it would be hard to beat a Sherwood Brut or Magnum 1st stage and a metal USD 2nd. You could buy on eBay and have them professionally serviced and still have change from $100.

 

[elan]

@Fishpie
I bought just an MK17 from an authorized dealer 2 months ago... And SP allowed me to register it. So I guess it can be done.

@halocline
The new S600 with a metal barrel seems to be on par at least with G250 in terms of cold water. I was diving my upgraded S600 on MK5 (no sealing) in 39F yesterday (25F outside), no hassles Depending on the local conditions (presence of springs ) we normally find the water in a range of 36-39 under the ice. But absolutely an all metal 2nd with MK17 would be a winner and that what I would get if I was going under the ice on a regular basis. For me a an unsealed piston or an unsealed diaphragm is a no go for repetitive dives in below freezing surface conditions. The spring just freezes if you take it out of the water to switch the tanks for example.

 

[halocline]

Elan, if you have the later model MK5, with the small holes in the ambient chamber, you can easily pack the chamber with PTFE grease or silicone. I did that (I used the less expensive tribolube) on one of mine, mostly for grins as the coldest water I usually dive in is about 68F. It sure keeps the chamber clean!

 

[elan]

I will try to do it with one one my MK5s on the next service - all my 5s are with the small holes , I just need to order a tonne of tribolube

BTW. sent you a PM