SP MK25/250 vs MK25/550

[MSP]

which breathes better and would be great for warm water dives. I am new and can't decide between the two. I have seen alot of post about the 250 but haven't seen much about the 550.

Thanks

 

[matt_unique]

which breathes better and would be great for warm water dives. I am new and can't decide between the two. I have seen alot of post about the 250 but haven't seen much about the 550.

Thanks

I believe this is the only difference. (Costs a few bucks less too).

--Matt

 

[WaterDawg]

If the cost is around the same, go w/ the 250 the 550 isnt adjustable and isnt all that high proformance if you ask me, I now use it as a back up. I know some folks have been using the 250 for years and is quite the workhorse.

 

[QuoVadis]

I have an Mk25/S550 and it's awesome...

 

[redacted]

If user adjustment matters, go with the 250. If size matters, go with the 550. If they both matter, look for a 600. None of them will breath better than the 250.

 

[oceanrealm]

which breathes better and would be great for warm water dives. I am new and can't decide between the two. I have seen alot of post about the 250 but haven't seen much about the 550.

Thanks

I bought MK25/S550 in June and did only 3 dives with it so far in Monterey, CA.
So, based on these 3 dives -
I have not experienced free-flow at all.
It breathes fine - actually my air consumption improved with this reg.
I loved a swivel on first stage - no tension in neck or jaw fatigue
And at last - price was OK for me. I bought it from my LDS. I took advantage of ScubaPro promotion (got $50 back) and store manager gave me some free diving accessories in compensation for sale tax. Altogeter it cost me $364.

 

[DA Aquamaster]

The S550 and S600 are essentially identical with the only difference being the S600's adjustment knob.

The S600 and the G250 are also essentially identical with the only difference being a larger case and diaphragm on the G250.

I personally think there are some real engineering advantages to the larger diaphragm used in the G250 given the forces and leverages involved in operating the demand valve in the second stage. Theoretically, a G250 can be fine tuned to breathe a little easier due to the larger diaphragm but both the S600 and G250 come adjusted to breathe a lot harder than they have to from the factory (to comply with CE norms).

I have also never seen any practical advantage to having a smaller second stage and feel that most of the perceived need by divers to have a smaller second stage is mostly the effect of marketing hype. A larger second stage is slightly heavier, but it also displaces more water so the net in water weight difference is zero and a smaller second offers no real benefit in terms of preventing jaw fatigue.

Proper mouth piece design and selection and proper LP hose lenght have a LOT more to do with preventing jaw fatigue, TMJ, etc.

 

[crosing]

I had the mk25 and s550. It free flowed on me 3 times in 41 degree water. I sold it and got an Apeks200 atx and could not be more pleased with this new reg!

 

[BDub]

Theoretically, a G250 can be fine tuned to breathe a little easier due to the larger diaphragm but both the S600 and G250 come adjusted to breathe a lot harder than they have to from the factory (to comply with CE norms).

DA, I'm curious. How do you 'fine tune' the G250? I have one and while it breathes awesome, I'd like to know how to fine tune it a bit more.

 

[reubencahn]

I have an S600 with an S550 backup. If I had to do it again, I would take the G250 with an R380 backup. Neither the 660 nor the 550 are worth the extra money.