yes they are however people need to know the design and that the very small leak of air that you will see coming out of the rubber over pressure port is normal and part of the design of the regulator, over the course of a dive the amount of air is very very small,
It's a Closed system because of its "Dry Air Bleed" system. This is where the piston has a port that allows air to pass through it at a nominal rate and equalise the two chambers. It is a very clever design and efficiently sidesteps the deficiencies of both 'piston' and 'diaphram' designs without letting water into the regulator. It does have its own limitations (notably the small leaking air from the 1st stage - everyone after a dive has to tell you your regs leaking!), but when it was first introduced Sherwood was SO confident in it's system they offered a life time warranty on ALL parts - including internals. They could do this as long as the reg.'s seals were never breached. Indeed, my Maximus I used for 25 years without shop servicing - all a shop servicing consisted of was to measure the air release mechanism and make sure it was 13mls of air at sea level. I'm a Sherwood servicing mechanic. If the reg fails, it fails in the open position so you still get air to breathe to get you to the surface.
Having a hearty piston reg can be a great option for cold water regs. I've got a MK25EVO that's essentially bulletproof even in 34 degree water. They include the anti-freeze/drip tech that helps enable the water to drain off the first stage goes a long way.
34? That is a summer temp in Seattle. 42 surface, 32 at 5 meters, Jul to Sep, not been in OW in Oct. Mostly Kelp, crabs and wrecks with seal and boat noises everywhere.
Great explanation. In 30 years I have used both systems. I did ice dives with the old mk10 piston and they didn't freeze. Mk25 in a colder water (autumn) did but when my mate jumped in, he inflated his suit, bcd and was getting used to the cold on his face so heavy breathing. Expanding air cools temperature. That explains the freeze. All depends on how you use it I guess. The mk2 is a great 1st stage, but under 30m I preferred some more air flow, mk10 or mk25, mk17 and ds4(apeks) did function well there as well. I wouldnt hesitate diving simple shore dives in season in the Netherlands with an mk2. But if you want to invest and have the money, I would advise on the mk17. The mk25 is more expensive and doesnt freeze either when used and maintained well. Ask yourself what kind of dive you will be doing in the next 5 years. If you are really serious invest a little more. If you just go on holiday to the caribs get the mk2, they can service it there blindfolded in an hour is needed. All DC's have service kits for the mk2 around. Thats also worth something right.
I bought a piston for the simplicity factor. I am probably going to do mostly warm water diving, I think 50 will be my limit for cold and that will not be very often at all. Bonne Terre mine being one of the few cool water dives that I would like to do. If I end up doing anything colder it will be in a dry suit with a full mask and setup for that and I will just rent it. The simplicity factor on the MK5 and MK20 that I have is their saving grace for me, I rebuilt them and can do it cheap. I know more than a few dozen will complain and they always do, but simply put do I really know and trust the guy and random shop "A" or random shop "B" or do I just walk in and trust them... I would rather trust myself to get a good nights sleep, not have other junk on my mind, and know I am putting my life in my hands. And same goes for rental equipment so honestly I doubt I will be renting any to do super cold water diving either. Regulators are regulators, as long as they work well with minimal issue/maintenance and do what you need it to do that is what you should use.
In my opinion the biggest change in first stage regulator design, in the last 50 years was the balanced diaphragm regulator external hose layout. Some now have the same hose layout as a balanced piston regulator.
I think you left a lot out of the discussion here. Plus I'd be wary of purchasing Scuba Pro here in Australia any more as I've been told by a stockist that they don't want tp know about any warranty or spare part issues. I know I've tried getting parts for my BCD. After spending 0ver $1K, it's a bit late to tell me that I can't get parts !!! So No more ScubaPro for me.
I’m finding this issue with something simple as getting O-rings for MK 25 first stage looked all over on internet … thinking about going back APEX 🇬🇧🏴
I am a 40-year Yoke/Ballance Psiton design regulator diver in Seattle Washington. The water is cold 43F degrees, so I use a 7mm wetsuit. I am not Ice Diving in a lake.
GREAT JOB JAMES. you took a basic question and made it simple. been servicing equipment for 30 years and you nailed it. it is up to what features people want and what is offered at their dive shop. they all will do the same thing within limits. Keep up the great work.
Agreed, the best one is what's best for you. And I've had 2 of us at 40 metres breathing off one Apeks DST, as shown here, for a demo and it gave just as much air as we could take.
Hi, just wanted to say thanks for an informative and clear video. I've just started my BSAC course and it's in my nature to be very inquisitive about how stuff works, especially in this case where my life depends on it. Thanks again 👍👍
very good information, I do believe that this topic should be well covered in a Open water course and this should be a very good review for any diver with a Open water certification
Ugh, I thought I had this narrowed down to one regulator for purchasing. I was going to get the AquaLung LEG3ND Elite. It's a diaphragm first stage. But I'm liking the idea of the piston design because there are less parts. 🤔 Back to researching.
Mostly depends on how you dive, comfort vs feedback. If you dive properly the resistance of one is pointless but tech nuts love to push it to the edge. My wife has anxiety about the issue so I got her the Aqualung Legend. It is so smooth and it helps her relax. I know from the "out of air" exercise. I was using a rented reg. It was like going from a Corolla to an Avalon.
I have and use both piston and diaphragm regulators. Both have their place. Regardless of the hype from the manufacturer's first stage regulator design has changed very little in 50 years. We still use the same basic first stage designs unbalanced piston, balanced diaphragm and balanced piston. So there must be a place for each or manufacturer's wouldn't still make all three.
We dive cold water even in summer here in Germany. As soon as you dive below the thermocline it will get cold😅. The mk25 from Scubapro is very common in the tech Community over here, eye to eye with the Apex. I myself had never any issue even below 4 degree Celsius.
This will probably generate some discussion. In my opinion winner's in the following categories. Initial cost > unbalanced piston. Cold / polluted water > balanced diaphragm. Hose layout > balanced piston and most of the newer balanced diaphragm. Deep Water > again balanced piston and balanced diaphragm. Cost to maintain in order from least to most costly (cost of parts for service) > unbalanced piston, balanced piston, balanced diaphragm.
I love my XTX50's and Tek3's! They work great up here in Northern Michigan! I took my XTX50 to my ice diving class in March, and despite trying to make it free flow at the end of one of the dives, it wouldn't! Not to say it can't or won't at some point, but it didn't then. Off topic, but I see the Blacktip in the background. Just curious how you like it. A group of us up here purchased some in December/January and we all love them! It's always fun zooming past other divers at the local evening dives! Especially on those dives where it's close to a quarter mile swim out there!
Hey! I am sending Alec a link to this! He is untouchable, not really. I am sure he would admit he makes such simplifications too. It is more a product of the media than the person. Simplify but be complete too. It is why I post about a tenth what I could.
Love the videos! Where can I get a rebuild kit for a scuba pro mk2? I have one that I dive with but can only find repair kits for it on ebay. My last kit was older than me! Thanks
@@toriless That is slowly changing. From what I have seen, most divers that are going towards the technical side are switching to DIN. Recreational divers are slowly following. But, are the advantages of DIN worth replacing a perfectly good older regulator you already have if there are no DIN kits for it? My local dive shop carries almost exclusively DIN regulators.
What cold water temperature range would "cold-water performance" regulators be recommended for? Curious about the uper range? When is frost/ice a risk? Tha lnks
Hello from Greece, Firstly, i would like to mention that i am a fun of yours and enjoy your videos. Secondly, i am not sure if my question is stated correctly, but can you recommend a first stage regulator for nitrox and cold water?
General question. I've just heard about a fisherman who survived for three days in an air pocket in a sunken boat at 100ft, 30m. Divers going to find the body, found him alive. How ling would the ascent need to be, assuming no pressure chamber on the rescue boat?
The cold temperature is significant!!! If I go into a cool pool at first I can hold my breathe 30 seconds, after half an hour it is over 4 minutes and that was decades ago before I read a free diving manual. I would toss pennies and retrieve them. Also move SLOWLY. It is huge. It is almost like a human version of hibernation. Well, this is what happened to me, your results may vary.
@@toriless i used to be able to swim 2 lengths of a 25 yard / meter pool. As you say slow and steady was the way. I always thought that it was funny, the next time I went I struggled doing a width at first then over the session I got further and further.
James, your comparison of mk2 and DST (yes, the Apeks 1st stage you showed is, indeed, called DST) is not necessarily fair. The DST is environmentally shielded version (unshielded version is called UST). On the other hand the Scubapro MK25 is environmentally proteced version (the t.i.s. kit) of a piston reg. Apeks UST and US4 are not protected and water will reach the inermediate pressure control spring and the diaphram so those are vulnerable for freezing, too. Therefore those models should not be used in colder than 10C water. The technology (diaphram vs piston) does not define if the reg can be used in cold water. I've had both and those have workedfine even during ice dives.
The TIS system isn't an environmental seal like you see on diaphragm regs. It is a coating that slows ice build up combined with plastic pieces that slow cold transfer from metal to metal parts. Scubapro did make an environmental seal for piston regs using the Spec boot, and Atomic still does.
Why I switched from Atomic (piston) to Hog (Diaphragm). Cristolube is expensive. In order to use a Piston, in Cold or silty water it needs to be sealed. Atomic uses Cristolube (i do not know what everyone lese does) . This crap is stupid expensive, doubling or tripling the price of rebuilding the Regulator. A little tweaking of the second stage and the Hogs breathe as well as any regulator I have ever used and at much better price.
No not all diaphragm regs are sealed. I have unsealed version of the apeks (called UST, Un-Sealed with Turret) and some poseidon regs, also diaphragm and not sealed
Sorry Alvaro, to be fair to James, Apek have used XTX for both first and second stages for years. My own identical reg has APEKS and XTX embossed on the first stage.
I have no idea what you mean but I use VERY dilute baby shampoo for mask defogger. I keep having to dilute it more. Anything else is waste of time and money. Thanks J&J.
