Gas Analyzers

[Nwcid]

As some of you may have read we are interested in nitrox and in the future probably trimix. In our area there is no way to get either so PP looks like our best option. I am about 1/2 way through reading Oxygen Hacker's book for the first time (will be re-read many times). Obviously one thing that keeps coming up is being able to check your mixes to make sure you did your calculations correctly.

I know they have home built testers in the book (have not gotten to that part yet) but I think this is a piece I would like to buy commercially. This is where the question comes in. It looks like I can buy an O2 analyzer for under $200. When we do get into doing trimix it looks like we will need a different analyzer for that which seem to about $800. So the question is while the trimix one is more expensive would it be worthwhile to just buy it since it will do both?

Are there advantages/disadvantages to each?

[Joshua Smith]

If you are definitely going to do trimix, just buy a trimix analyzer. Its all I use.

[pensacoladiver]

As far as the home built analyzers, they are every bit as good as any you can buy. I ordered one of the el cheapos from oxycheq and then I built one of my own from scratch ordering parts online.

Both work perfectly and I built the second one for less than 100 bucks.

The heart of any analyzer is the sensor and you will find that brand name units use the same sensor as the el cheapo.

I also have a trimix analyzer but ain't figured out how to build one of those yet.

[Jeff Pack]

same as Josh, I only use O2 analysers in my mixing station. Tanks I use my trimix analyser as a double check.

[Nwcid]

I was not so much concerned about the function of the homebuilt unit. My thought was the commercial one is more compact and less easy to damage if used with traveling. Maybe I am wrong on this point as I have not read that section yet.

[pensacoladiver]

It all depends on which commercial unit you are talking about. You can make the DIY unit as small as you want with whatever size "project box" you buy.

Other then that, it's just several wires, a knob, a switch and a pcb in the box with a battery. Pretty damn rugged design.

The whole thing can fit in a small padded pelican case for travel.

Not trying to sell you on it, but they display the same info a professional built one does at a much lower cost


Plus there's just something cool about making your own.

[Nwcid]

Sounds good. I will look forward to getting to that chapter then

[Tangfish]

I love my Divesoft analyzer. See if you can find one used somewhere.

[Dusty2]

The problem with buying used is the oxygen sensor is the most expensive part and they have a finite life span and most used units will either have a bad one or be almost worn out so you ens up paying another 75 to 100 bucks above your unit cost. Remember to factor that into your cost. Building one from oxycheq's kit is not rocket science but you need to do some soldering on the printed circuit board and read the instructions carefully. They have an option for a 10 turn pot for the kit. I would recommend you go that way because it is far easier to calibrate accurately and get it to hold.

[Jeff Pack]

On most units the helium cell is the most expensive... around 250$ I think on the divesoft. O2 cells are 1/4 that.