Looking at ScubaPro...

[uberspeed]

I have been told that they have great regs, used MK2 for a while and breathed well, I had no issues. Figured I can get the MK2/R190 until I become an instructor and then get something like the MK25/G250HP (I'm thinking this would be fine for technical diving as well?). I dive warm waters only, any preference between diaphragm and piston? Thanks for the help, I didn't want to hijack anyone elses thread.

 

[brssmnky]

I have been told that they have great regs, used MK2 for a while and breathed well, I had no issues. Figured I can get the MK2/R190 until I become an instructor and then get something like the MK25/G250HP (I'm thinking this would be fine for technical diving as well?). I dive warm waters only, any preference between diaphragm and piston? Thanks for the help, I didn't want to hijack anyone elses thread.

I use the MK16/G250HP and really like it. From what I understand, the 16 delivers less cubic volume on demand, but I got it because it is a sealed diaphram (I plan on going into cold waters eventually). From what I'm told the G250 has the same insides as the S600, just a larger housing. I think (someone please correct me if I'm wrong... and I know someone will) the MK25 is a piston 1st stage which is simpler in design and therefore less likely to have something go wrong (in warm waters anyways).

 

[uberspeed]

Yes, the MK25 and the MK2 both are piston. The MK25 being balanced, the MK2 not. Since I'm exclusively in warm waters I plan on using a piston design since I have heard it's better suited. Thanks for your input.

 

[DA Aquamaster]

The flow rate on a Mk 25 is approx 300 SCFM. This is basically the flow rate you would get if you removed the end LP port plug and turned on the tank valve.

That much flow rate is mostly overkill as anything over 100-110 SCFM is considered high performance and is adequate for even deep technical diving. If you get real deep, you end up with a sibstantial amount of helium in the mix and the helium slips through regs better than air.

The Mk 16 has a flow rate of around 90 SCFM and is consequently at the upper end of the medium rather than high performance range in terms of flow rate. But unless you are going well beyond recreational depths, it is more than enough air. It also delivers about twice as much air as the MK 2.

The parts count on the Mk 16 is substantially higher than on the Mk 25, which is pretty much the case when comparing any diaphragm first stage with a piston first stage, so the MK 25 is easier to service and potenially more reliable. A very simple piston design like the Mk 2 extremely bullet proof. The MK 25 has a higher parts count but is still relatively simple.

The Mk 25 uses a bushing system to hold the HP o-ring in place and to guide the piston. The bad news about this desogn approach is that the bushing system requires service (replacement) every year or two but the good news is that it is not subject to HP o-ring pinch at high pressures, the primary parts that wear are replaced during the annual service so the MK 25 should last for decades even with heavy use, and the parts themselves are really inexpensive.

The Mk 2 and Mk 16 make better cold water regs as the Mk 25 can be prone to freeflow in very cold water unless low pressure tanks and a fair amount of care is used.

As indicated above, the G250HP has the same internal components as the S600 and the only difference is the larger case and diaphragm on the G250HP. The larger diaphragm in the G250HP conveys a potential performance advantage over the S600 but most users will not see it unless it is tuned to breathe with a lower cracking effort than the factory specs.

The factory specs for cracking effort on all of SP's second stages is higher than the regs are capable of achieving due to the percevied need to meet CE norms regarding freeflow resistance. (This trait is common to every other reg manufacturer who caters to the european market as well. ) SP has also plugged one of the aspirator ports in some of their models to meet the freeflow standard at the expense of some potential performance.

So in my opinion for max performance and ease of breathing the MK 25 G250 HP is hard to beat.

 

[rescuediver009]

I would agree that the Mk2 is something nice tostart with and you would not likely be disappointed. But beware this is not a reg that will grow with you very long. I would say that once you have your advanced you would likely enjoy an upgrade. Waiting until your instructors is even longer. Take a look around though, there are alot of models between the bottom and the top... look midrange at the 390 or 550. Don't discount diaphragms either. As DA said the 16 will be a better performer than the MK2.

Don't get caught up in the complications though. Make your choice on advice from someone youtrust and respect.

 

[akscubainst]

I guess since you are a fellow paintballer and appear to be an Angel owner would you play with a Spyder? The MK is to diving what the Spyder is to Paintball and the MK25 is equal to the Angel.

If you can't afford the Angel/MK20 then go middle of the road with the MK16/Autococker.

Dave

 

[uberspeed]

Great info people, thanks!

AK, I completely understand what you're saying, great example; I knew that going in. I just need an inexpensive and reliable setup to get me going until I get serious (which I'm already planning on doing) and then get better gear down the road.

DA, that's great info indeed, thank you very much. If I gather correctly from your post, the cracking effort should be turned down? If so, I'll run a search to gather that info, thanks for the tip.

rescue, the reason for starting cheap is I have 2 people to outfit, not just myself. Makes the proposition a bit more expensive. If I start with MK2, then once I become an instructor I will most likely have access to discounts and then can splurge on something substantially better like the MK25 that I have my eye on. Thanks for the advice, much appreciated.

 

[DA Aquamaster]

The Mk 2 is normally packaged with either the R190 or R390 while the Mk 16 is normally packaged with the more expensive R390 and S550.

It is not marketed that way, but your dealer can order a Mk 16 with an R190 second stage and in that case the cost difference falls to only about $30 over the cost of a Mk 2 R190. Most of the price difference between the Mk 2 R190 and the Mk 16 R390 is in fact in the R390 second stage.

If SP normally packaged the MK 16 with the R190 it would be their best selling "entry" level reg and very very few Mk 2's would be sold as the Mk 16 is balanced and offers about twice the flow rate of the Mk 2 for anopther $30. The Mk 16 is a steel of a deal if you can avoid buying the overpriced R390 with it.

As it is SP only packages the MK 16 with the more expensive R390 or even more expensive S550 and consequently creates a substantial price difference and in effect maintains "entry" and "intermediate" level regulator packages.

The R190 is identical to the R390 with the exception that the R390 has a smaller case and diaphragm. Breathing performance is identical from the factory and like the G250HP / S600 comparison, the R190 potentially benefits from the larger diaphragm.

So if you are equipping two of you on a budget but want the most bang for the buck, special ordering a pair of MK 16 R190's is the way to go.

 

[ShakaZulu]

I hope you are looking at Apeks too.............These toys are exspensive, buy right the first time.

 

[uberspeed]

I hope you are looking at Apeks too.............These toys are exspensive, buy right the first time.

I've just been looking at piston designs really. I looked at Apeks but where would I get it serviced? In So. Fla. I can get the SP serviced easily and that's a selling point to me. Since all of my diving will be in warm water, I thought piston was the way to go, no?