What is the maximum operating capability of a Scubapro MK2?: Your opinion

[Eric Sedletzky]

I’m just curious to see what peoples’ personal opinion/comfort level is of how far or how aggressively they would push a MK2.
What do you think it’s capable of as a primary regulator for single tank diving?
I know it depends a lot on the second stage.
For fun lets pair it with an R195 as the back up and lets use a G260 for the primary.

 

[lowwall]

I'm not sure I understand the question. It's not recommended for extreme cold, but it will function deeper and colder than I will.

 

[cerich]

also depends on what gas choice.
From experience, far beyond recreational depth. I have used with air deeper than i am comfortable posting here, but didn't exceed a PPO2 of 1.63 or so.

 

[lowwall]

also depends on what gas choice.
From experience, far beyond recreational depth. I have used with air deeper than i am comfortable posting here, but didn't exceed a PPO2 of 1.63 or so.

Ooh, a quiz.

1.63/.21 - 1 = 6.762 atmospheres of water = 67.62m or 222ft. Or so.

 

[nickbutcher]

I’m just curious to see what peoples’ personal opinion/comfort level is of how far or how aggressively they would push a MK2.
What do you think it’s capable of as a primary regulator for single tank diving?
I know it depends a lot on the second stage.
For fun lets pair it with an R195 as the back up and lets use a G260 for the primary.

The Mk2 is practically bulletproof. It'll deliver more gas than you could possibly breathe at any depth you would sensibly take a single tank.

I would happily use the ones I have lying around in my spares 'box' as deep bailout regulators if only they had marginally better hose routing.

They are one of the easiest regulators to service and are very flood tolerant.

 

[Angelo Farina]

It was discussed here recently the history of the fifth "high flow" port of the MK5.
This was added for matching thr performances of the MK2 for very deep diving in air (70-100m).
US Navy conducted tests on several regulators and the MK2 was delivering more air and with more constant IP than the MK5.
This means that tbe MK2 is one of the best regulators for diving deep and with a dense gas (air).
The only known drawback of unbalanced first stages is that the IP changes slightly with tank pressure. You can perceive this only if matched with an unbalanced second stage, such as the 108 or the original 109.
When using a balanced second stage (109 BA, 156, G250, etc.) this problem disappears.
So the answer is that the MK2 has no practical limit regarding depth.
And the modern MK2 Evo DIN can be used also on 300 bars tanks...

 

[cerich]

Ooh, a quiz.

1.63/.21 - 1 = 6.762 atmospheres of water = 67.62m or 222ft. Or so.

I didn't say fresh or salt

 

[cerich]

The Mk2 is practically bulletproof. It'll deliver more gas than you could possibly breathe at any depth you would sensibly take a single tank.

I would happily use the ones I have lying around in my spares 'box' as deep bailout regulators if only they had marginally better hose routing.

They are one of the easiest regulators to service and are very flood tolerant.

naw, I wouldn't with air at deeper than I have dove it, it was acceptable but starting to show it's gas flow limits with air, with helium in the mix obviously will be better and ok a bit deeper. But even for Tmix Bail out doing deep I will choose a higher flow reg.
It was a LONG time ago when I was a Cayman Instructor that I started using Mk2/R190 as my work regs because had set up my doubles with my MK10+/G250's. When I took the MK2 that deep, the decision to use one of the Mk10+/G250's when doing deep or even guiding wall dives was made that day, I had chased people deeper before and didn't want to do a chase to 300 using the MK2.

 

[Angelo Farina]

Here data from the Scubapro catalog 2023.
For the MK2 (piston unbalanced):

• Airflow at 2900psi: 2600 l/min - 92 SCFM

For the MK17-MK19 (diaphragm):

• Airflow at 2900psi: 6900 l/min - 244 SCFM

For the MK25 (piston balanced):

• Airflow at 2900psi: 8500 l/min - 301 SCFM

Also consider that the top second stage from Scubapro, the D420, can flow "just" 2000 l/min - 71 CFM. Most other second stages (S600, G260, etc.) can flow only 1800 l/min.
So a MK2 can fulfil its demand without problems. It can be limiting only if feeding TWO D420 simultaneously...

 

[ginti]

Fere data form the Scubapro catalog 2023.
For the MK2 (piston unbalanced):

• Airflow at 2900psi: 2600 l/min - 92 SCFM

For the MK17-MK19 (diaphragm):

• Airflow at 2900psi: 6900 l/min - 244 SCFM

For the MK25 (piston balanced):

• Airflow at 2900psi: 8500 l/min - 301 SCFM

Also consider that the top second stage from Scubapro, the D420, can flow "just" 2000 l/min - 71 CFM. Most other second stages (S600, G260, etc.) can flow only 1800 l/min.
So a MK2 can fulfil its demand without problems. It can be limiting only if feeding TWO D420 simultaneously...

What is a "liter" in the l/min you show? Is it a liter at 2900psi, or a liter at atmospheric pressure? I assume it is the second, right?