Vintage Double Hose

I read a lot about the S.P.E.C. or environmental kits that were available years ago for the MK5 and other Scubapro regulators. Does anyone have any experience using a MK5 / R109 in cold water without that kit? Most of my diving has been in the tropics, but recently my daughter moved to northern California and frequently dives in the Monterrey Bay area. I guessing the water there is somewhere between 40 and 50 degrees F this time of year. Would a MK5 require the environmental chamber to dive in that temperature water? Or would it be sufficient to fill the chamber with silicone grease? Or should I look for a more modern regulator that may be more suitable for that type of diving.

Any advice would be welcome

Thanks

I dove Monterey for years with a MK5/109 without any environmental mods. Dove British Columbia a bunch with same reg - no cold water mods. Mark.

Even though NorCal water is cold, it is nowhere near freezing, so cold water mod's are unnecessary.

Does anyone pack the ambient chamber with silicone grease? I think I remember one of Bryan's videos on the MK5 where he rebuilt one sent in from a customer that had the chamber packed with silicone grease. Is that required only for ice diving or should that be applied to any MK5 regardless of the diving conditions?

Thanks for the replies

My group of buddies and I routinely dove the MK-10/109 & 156 in Lake Erie in the 90's (and likely a MK-5 was in the group, but i didn't know the differences back then). Temps were in the mid-to-upper 30s at depth. Rarely had problems, and if we did, it was more user error than the regulator not being capable. We did not pack the ambient chambers. I'd venture to say the MK-5 would be much the same. That being said, I wouldn't dive it under the ice...

Thing is, we also didn't tune them on the edge. I watched many MK-20/25 stages (and plastic seconds) not tolerate the cold. I think hot tunes are problematic, and need to be avoided in the cold.

YMMV