G250 Crystal and MK20 Ultra Lite

[halocline]

That's what I'm looking for, a similar layout with swivel and 5 LP ports. I was thinking the MK10 would be a good easy to find option but possibly the MK15 too. Which would be better for cold water?

It kind of sounds like your question has been answered, but for really really cold water, like below 40F, packed MK10s would probably be better. By 'packed' I mean the ambient chamber is filled with silicone or PTFE grease and there is a boot containing the grease that fits in a groove in the reg body. With the boot on they look a lot like atomic 1st stages, imagine that. Anything warmer and you probably won't have any freezing concerns.

 

[Slamfire]

On really cold weather you might get 44 or maybe 43 degrees. More than often ocean temperatures around here stay between 46 to 52 degrees.

ferocious, below you will find an annotated schematic of a Mk10. I think brother couv produced this one. The numbers in red indicate the generic AS oring size. With these generic size numbers you can obtain orings from any industrial provider like McMaster Carr or Acklands Grainger. Just be sure to get the right material and hardness. I try to get my orings in viton duro 90 whenever I can. I've found that duro 90 still seals up all right in places where a duro 75 is specified and the extra rigidity helps against extrusions in high pressure applications. If I can't find a duro 90, duro 75 will usually work all right.

Conical sintered filters are pretty easy to get. The only other part that you might need to replace regularly is the high pressure seat. You can get a high pressure seat from Trident Scuba. Trident only sells through dive shops so you might have to go to any dive shop and tell them that you need to order part # A242 found on page 50 of the 2013 Trident catalog. Usually you can get each for less than $5. Order several. If any given dive shop is uncooperative order them online though a store like Scuba Toys. Once you have access to seats and orings you basically have the annual rebuild kits. You can service your Mk10s for about $5 each.


View attachment mk10 annotated.pdf

 

[ferociousfish]

Thanks everyone for all the awesome advice and info! Definitely answered my question and then some!

 

[ams511]

You may want to consider replacing the G250 Crystals also. They seem to have a high value as a collectible.

 

[ferociousfish]

What's so special about the G250 Crystals and how much value? I was planning on using them as any regs, but maybe I should do some research first.

 

[ams511]

What's so special about the G250 Crystals and how much value? I was planning on using them as any regs, but maybe I should do some research first.

My understanding is that the Crystals were never part of Scubapro's catalog in the US, so they are rare in North America. There is some guy on ebay trying to sell one for $500, which I think is high. But I would think that if yours are in good shape you could probably get $250 or more for one, which is about twice the going rate of a plain G250 on ebay.

 

[ferociousfish]

Wow, that actually makes sense seeing as the guy I purchased mine from brought them from Africa. $500 sounds good, but it's one thing to ask that much and another to get it. I'll watch that ebay listing. Thanks for the heads up!

 

[Iseebigppl]

My understanding is that the Crystals were never part of Scubapro's catalog in the US, so they are rare in North America. There is some guy on ebay trying to sell one for $500, which I think is high. But I would think that if yours are in good shape you could probably get $250 or more for one, which is about twice the going rate of a plain G250 on ebay.

He has been trying to sell that for a looong time. I'd be willing to trade a like new g250v and a little cash for one, but 500 is beyond ridiculous.

 

[Zung]

They sure look pretty. I paid $80 for mine, I've seen them go for as high as $200, but $500 is outrageous.

 

[Couv]

They sure look pretty. I paid $80 for mine.......

So now that it is older and used more, I'll give you $60 for it.