Oxygen analyzers--which type is better?

[BigTuna]

Are flow-thru analyzers or flow restrictor analyzers better, and why?

Flow-thru analyzers like Analox and OxySpy seem simple to use. They're easy to take along and don't require extra parts. But could their accuracy depend on how you hold the inlet against the tank valve?

Analyzers with flow restrictors, like OMS OX-AN, OxyCheq Expedition, and DiveRite Maxtec MaxO2, require keeping track of a tube and a dedicated first stage or LP connector. Is the extra complexity worth it?

DiveRite has one that can be used either way--the Maxtec Handi. When would one use it which way?

For any of these, how do you know when the oxygen sensor needs to be replaced? Do they flash lights or something?

 

[Brian Gilpin]

I to am interested in the answers. Hopefuly someone knowledgeable will chime in.

 

[pescador775]

For stik use, the "flow by" Miniox III can be had new, MIL surplus for $100.00. All the bells and whistles and really nice. For portable use, the little, one piece, "flow through" Analox gizmo is great. This device has a built in restrictor and exhaust port. You will know if the sensor is weak when the unit won't calibrate. True, there is a technique to using the little guys with their pinhole restrictor. Don't crack the tank valve beyond bleed. The analox don't work well on combo valves which have a screw in insert. Too much of the gas flows by (bypasses) the restrictor. Relax, these machines are a lot easier to use than that computer which you are typing on but you will need an adapter for the combo valves or better, use the big enchilada with the clamp on first stage and Miniox box and sensor fitted with 3/8 npt/1/4 modified plumbing adapter to screw in the sensor and connect to the regulator through a plastic tube, as in Vance's book.

 

[CompuDude]

Which Analox gizmo? How much to those run? I've been thinking of getting an analyzer of my own, but have been content to use the one at my LDS for now.

 

[PerroneFord]

I've used both kinds. Gotten consistent results using either one. I normally grab the Oxyspy and go. Easy. I need to buy an analyzer in the next couple of months, and I'll probably end up with something from OXycheq. Good price and performance. Simple, and fits in a small pelican case.

The Analox is nice too and I wouldn't mind having that. The Oxyspy (shop's) is just a bit long and cumbersome.

 

[*Floater*]

I'm also interested in this question. Previously I had assumed the analyers were all about the same, but my tech instructor did not think so. He claimed that the resort where we were staying at had gone through a number of analyzers, which had broken under heavy use, until they bought the Alpha-1 Oxygen Analyzer (ANDI product) which he was promoting. He was an ANDI instructor though, but the resort wasn't so I don't see why they would have spent the extra had they not felt it necessary... or maybe they got a special deal.

In any case, I'd like to hear from scuba professionals, especially ones that work in a shop where tanks have to be analyzed every day. What do you use? Do you find a big variance among brands and models in analyzer durability and performance? What about for casual divers, say for divers who analyze 100 tanks max per year, are most analyzers durable and accurate enough?

 

[PerroneFord]

I am not a dive pro (obviously), but do work part time at a cave shop. Fills on everything from custom nitrox blends, to heliox. The oxyspy gets it done for the nitrox stuff, and it gets tossed into the van and goes to the site (in it's provided padded bag).

You might want to PM Curt Bowen or GDI, and ask them what they take on expedition around the world.

 

[MilitantMedic]

Best value is the Oxycheq Expedition. Small, simple, robust, backlit LCD screen, you can use the directly to the tank valve, use a BC QR fitting, use a DIN fitting, use a yoke fitting....you can keep going on. They are easy to fix and easy to get parts for.

TDL is selling expedition right now for $200 (it's blue and says TDL, but it's an Oxycheq). Personally I built my own, mostly becuase I'm the tinkering type.

 

[pescador775]

I've seen the analox O2EII on Ebay, new, $200.

 

[rigdiver]

I've seen the analox O2EII on Ebay, new, $200.

I've seen these on may a dive boat. That speaks volumes. I bought one years ago and like it. Has a sensor saver. Mine is 3 yrs old now and still going strong.