First stage HP port question

[hlsooner]

We all need to know how much gas we have left in the tank, the method we choose to monitor it is based on our tolerance for risk of failure, as well as convenience for checking and other factors. The options include:

Analog SPG:
Pros - simple, cheap, very reliable, plus you get the classic needle drop when breathing if you do not fully open your valve
Cons - needs to be attached to a high pressure hose forcing you to check a second instrument, less precise measurements than are available via digital pressure transducer, notice I did not say less accurate, only saying it is hard to read any SPG I have ever seen to 5 psi increments like digital gives.

AI Computer SPG
Pros - becoming common, very reliable, gives the ability for the computer to calculate an estimated time remaining based on your actual gas consumption, alarms if your gas pressure gets too low.
Cons - Risk of computer failure taking away gas reading (I have had this happen once, but surfaced with no problems), needs to be attached to a high pressure hose forcing you to look down at a the computer

Wireless Computer SPG
Pros - all the same as AI computer, but also the great benefit of having it all on your wrist which you will check much more often and easily than any other mounting
Cons - all the same as AI computer, plus the possibility of losing connection between transmitter and computer

Having all dive information easily readable on your wrist is very convenient. However the added risk of failure is there, and if you are uncomfortable, or don't want to plan for, the risk of suddenly losing your gas data, then a backup SPG is your solution.

 

[DeltaWardog]

Follow up question - I have read elsewhere that mixing the Mikron 2nd stage with a different 1st stage is "not recommended".

Why not? Is it not a good idea to mix 1st and 2nd stages from different brands or models?

 

[scubafanatic]

...'mixing' brands can void warranties and greatly complicate servicing issues.....if you experience any servicing/repair problems the dealer will play the blame game and nobody will take responsibility...hope you don't have to learn this one the hard way.

 

[hlsooner]

Beyond the warranty issue, there is the concept of "Intermediate Pressure", or the pressure provided by the regulator first stage to the second stage. There is some variation between manufacturers on their ideal intermediate pressure, though not that much, so the concern is you might get a second stage being supplied with a different intermediate pressure than it was optimally designed for.

 

[DeltaWardog]

Thanks hlsooner, that is what I was looking for.

 

[Bob Vincent]

This will take some thinking ...

First off I just seen the Mikron in Key West at Divers Direct ... very cool looking. Why they didn't put 2 HP ports is just amazing. I also think I might go to the VT-3 on my next rec gear change.

But things do have a ohh ***** factor sometimes. To be safe swap for a VEO 250 if your going to still go with the Mikron. If not and still keeping the VT-3 buy a Legend or Delta 4 or even better the new EOS!

If you are an experienced diver and can make a free ascent from 130 ft easily, know the tables and dive profile without a computer and have it worked out on every dive and keep a second bottom time on your watch and be able to do a safety stop. And be very comfortable in ohh poop situations go for the 1 HP port. if not well you know ...

Ohh don't mix and match

 

[DeltaWardog]

I actually decided to go with a Kronos instead. Same price, has 2 HP ports, problem solved. Now if I could just figure out how to get a braided hose on it.

 

[Craig Winnerman]

I have an Aeris ai computer and had the battery explode on a deep dive. Must have been a real flluke with the battery, but I was literally dead in or under the water. Now I have a quick connect on my second HP port and keep an analog guage as a back up on deep dives.. glad to have 2 HP ports.

 

[bsumner]

I use the Aeris Epic (same as Atom 2), but do not trust it that much. It does go out occasionally and I want to know the available gas, so I always use a Cressi mini-gauge as a backup.

I do not use a SPG with my wireless Atom 2, I bought it to lose a hose. Wireless aint exactly skunkworks technology anymore- its pretty well proven. I have had no problems and bought an extra transmitter to keep tabs on the wifey. I glance often enough so that even if I should have sudden transmitter failure, I know about how much air I have and can ascend safely. If I'm wrong, I know the SPG on my pony says chock full.