Carbon Monoxide tank testers

[DandyDon]

I have had a few people private message me this week asking for suggestions, perhaps because of recent A&I threads. I've seen a few models come and go in recent years but then this is really recent technology. Not too long ago we couldn't even buy Carbon Monoxide alarms for our homes and developments in low PPM testing is even more recent. Awareness is lagging in the need for home alarms still with new deaths making the news every week, but more so with the need for inline compressor alarms as hardly any fill shacks have those. DAN gave one to the main fill station of Cozumel, but they often disable the alarms so they can keep running so the need for tank testing remains there as well as everywhere else.

I got one of the Analox CO testers when it came out and it was wonderful, but so many divers didn't want to spend that much money on something they shouldn't have to have, and a risk their Instructors failed to teach about, so they quit. I had the sensor replaced once and still use it. I also got one of the CooTwo units that checked for O2 & CO both and boy that was nice, but that company folded. Sad that the company couldn't do better in customer service which is probably what lead to its failure. I sent it to the shop offering repairs, but the motherboard was bad so no hope. I know of no other units that will test both gases at this time.

The PALM-CO Carbon Monoxide Analyzer is easy to use if you'll be diligent about testing for 30 seconds. I have not had one, but it looks like it can be field calibrated. The $400 price is discouraging and $200 sensor replacement after two years is as well.

The cheapest Sensorcon CO basic unit is the cheapest choice at $129. Good for at least two years, but I got a new one on sale instead of updating my old one last time, kept the old one out and on 24/7, and it's still working after 35 months. The risk of using one over two years old is that it might stop while on your trip. They claim that the computer software adjusts for calibration needs, and it is tough. I ran one thru a washing machine cycle once with no problems. I take enough gallon zip locks to use a new one each day as they develop leaks in the field. The bonus there is you can leave it on 24/7 as a backup home alarm and a travel alarm for your room as hotels seldom furnish those but they all have pool heaters, water heaters, and some central heating.

Nuvair – DE-OX CO Analyzer may be your best buy. $500 but claims a 5 year sensor life.

There used to be a OxyCheq Expedition Carbon Monoxide unit, and they may still make it, but I don't know - or how it could be used in tank testing. No one ever replied to this thread: Opinions on OxyCheq Expedition Carbon Monoxide analyzer?

 

[DeltaWardog]

Thanks Don. I am shopping for one of these now, and found it funny that a huge number of web searches for scuba CO detector lead to Scubaboard posts you made, as far back as 10-11 years ago. You truly are a champion for this cause! I am going to go with the Sensorcon / ziplock method I think. That seems like it will be good enough to detect a dangerous condition, which is all I'm really after. I'm curious, how many bad tanks have you found with this method, and what were the readings?

 

[DandyDon]

found it funny that a huge number of web searches for scuba CO detector lead to Scubaboard posts you made, as far back as 10-11 years ago.

Yeah, well I guess I am a bit of a fanatic. Not a week goes by that I can't find a few news stories about CO injuries and deaths above water. Here are three about boaters in the last month...

• York boat deaths prompt carbon monoxide safety warning - with deaths.
  
• Mother warns of carbon monoxide poisoning on boats, nearly one-year after losing son
  
• Man, daughters suffer carbon monoxide poisoning on boat

But are boat salesmen being rushed by worried customers or ever bringing up the risks themselves? There are several more land-based evacuations, injuries, and deaths with CO suspected, except it's actually difficult to prove as a cause as it dissipates so quickly, so those stories get ignored with a "Glad we weren't there" attitudes.

Then there's Scuba which is a potentially dangerous sport that we try to manage safely. The education, ability, and willingness to expose CO as a cause for Travelers' Flu, injuries, or deaths are just non-existent. Dive destinations seldom have the equipment to test nor the willingness to damage local economies by exposing tainted tanks. It's so convenient to write those off as illnesses or drownings. I know for a fact that a leading resort on Roatan lost a Texas tourist and a well-loved DM to CO tanks, but the resort tried to blame the Texan for the DM's death. The Texan's widow sued the Honduran resort and won, but she agreed in the settlement to not disclose how much or why she won. Back in 1979 a nearby city fire department lost three of their own on March 25, and the rumor I barely got was that they were fire department divers who got tainted tanks, but then my source shut up. Their cause of death is listed as "Other/Miscellaneous - Asphyxiation, Smoke Inhalation" which is easy to accept for firefighters. The hits keep on coming and coming, but accepted as "Glad it wasn't us" attitudes.

Back to scuba tho, with us breathing gases at two, three, four, and even more times as much effect, and sometimes we get down to even five or more atmospheres of pressure. I know that 130 feet is supposed to be my bottom, but aside from my one-time oops mistake, there have been other times when I've joined other divers briefly deeper. The CO risks increase with PPCO, partially offset by increases in PPO, but the big danger is ascending with the CO bound to your blood while the O2 drops. Complicated and hideous.

CO wasn't recognized as a real risk in the early days of the sport tho and we didn't have affordable technology to protect us. We know now and we do now, but what are the Instructors and Agencies still teaching us? "Smell & taste your air" even tho CO has no smell or taste. One recent news story reported a survivor who was injured by CO when floodwaters got into her home heater. She had a CO house alarm and it worked, driving her crazy even tho she couldn't smell any problems. With the vast majority refuses to educate themselves, I guess I'll keep playing chicken-little.

I'm curious, how many bad tanks have you found with this method, and what were the readings?

Not so many as I've slowed down in my diving in recent years so I just don't have a big survey. In 2004 on the first day of a group trip, I saw all of the air divers go to bed sick early in the day, while we nitrox divers who got our tanks at a more reputable shop had no problems. I now suspect that the shady operator we had went back to the fill shack, drained all tanks, and serviced his compressor - without ever explaining. We wrote it off then as Traveler's Flu, then.

When I did become somewhat educated and interested, I started trying different test units. I was on the way to dive The Catherdral in Cozumel as I had been wanting to do all week and was finally getting a shot on the last day, but then refused to dive deeper than 40 feet after testing. We turned the boat. Another time after 200 miles to dive a hole in New Mexico for practice, checking into a hotel the night before, we looked at my 5ppm reading and asked ourselves: We know we shouldn't dive these tanks but we have but two choices - dive these or go home. We shouldn't, but we did.

 

[DeltaWardog]

Well I've read too many stories of CO related deaths and injuries, diving and otherwise, to not take it seriously or leave it to chance. I installed CO detectors on all 3 levels of my house a few years back when I had an AC unit replaced, and I have a spare detector that I take on trips with me for camping and hotels. The last piece of the puzzle has been scuba tank testing and thanks to your work I think I'll have a workable solution. Thank you for your efforts. If I ever get a bad reading during my travels I'll be sure to let you know.

 

[DandyDon]

I installed CO detectors on all 3 levels of my house a few years back when I had an AC unit replaced

Great, and at least one for each bedroom I hope. Test on the first day of each month for continuity - press the buttons at least. I have been known to take my smoke alarms outside, build a small fire in a large coffee can with rags, and test with real smoke. Once I started my car in a closed garage to test my Sensorcon, but that's dangerous.

and I have a spare detector that I take on trips with me for camping and hotels.

Great. Take your Sensorcon on road trips to protect you from you car, then inside the hotel as well. Leave it on 24/7 as the battery is going to last two or three years.

The last piece of the puzzle has been scuba tank testing and thanks to your work I think I'll have a workable solution.

Thank you for your efforts. If I ever get a bad reading during my travels I'll be sure to let you know.

With a Report Thread and photos I hope.

 

[rhwestfall]

I use my Sensorcon to monitor my compressor output on fills (continuous), and for household and activity monitoring (working in areas or doing activities that produce CO)... Been very happy with mine.

I actually have the original plumbing kit from the old SCUBA testing kit they sold back in the day. It was a model for plumbing my compressor.

Oh, and they are made here where I live!

 

[asher102]

@DandyDon Have you looked at the Forensic Detectors waterproof CO analyzer? LINK

I have heard good things about their O2 sensors but I have not heard anything about their CO sensors. I am looking to replace my Cootwo.

 

[DandyDon]

@DandyDon Have you looked at the Forensic Detectors waterproof CO analyzer? LINK

I have heard good things about their O2 sensors but I have not heard anything about their CO sensors. I am looking to replace my Cootwo.

It sounds great based on their claims, which I presume are honest. Response time: 60 sec is going to bother some, allowing gas to escape for a full minute, but that's not a big amount really on a slow hiss. $169 with free shipping sounds great until you price the calibration bottle and valve as that will bump the total up. I'd call them, ask to speak to an engineer, and asks how much the sensor will drift over two years if I didn't calibrate.

They sell the Cal-gas bottles, valves, and tubing for $176 or more for the larger CO50 bottle, and some pros might want to get those. Recreational divers probably will either go with their calibration service or just try to adjust for drift. They suggest calibrating every 6 to 12 months, which costs $75 if they do it.

​

So if the sensor lasts 2 or 3 years, then it costs $56 to $84 a year.​

If they calibrate it for you every 6, 9, or 12 months, then that adds $75, 112, or $150 a year.​

Total costs would range from $131 to $234 a year depending on those variables.​

​

We'd need to know how much sensor drift to expect, but I suspect that annual calibration would be enough. My guess anyway.

If you don't want to spend that much, the $129 Sensorcon and gallon zip locks will work.

Or this $29 unit could work ok. It's not going to be accurate, but if you get any reading, reject the tank. Write the purchase date on the back with a laundry marker, then replace and recycle yearly for $29/year.

 

[NeesiePie]

Hi Don -
I'm late to this parade, but could you tell me how the ziploc bag method works? Put the sensor in the ziploc, then fill it with (tank) air?

Scubaboard apparently redacted your "this $29 unit could work ok" suggestion - could you repost?

Thanks! I really want to test, but I'm not made of money

 

[DandyDon]

I'm late to this parade, but could you tell me how the ziploc bag method works? Put the sensor in the ziploc, then fill it with (tank) air?

Yeah, that's about it. Take a box of gallon ziplock bags on a trip so you can use a new one each day as they develop leaks easily. Turn the unit on, drop it in the bag, squeeze as much air out as possible, crack the tank valve before putting the bag over it (I sent a unit overboard once by opening a cranky valve with the bag already in place), fill the bag carefully as to avoid ambient air entering with the tank air, close bag and close tank, and wait 60 seconds. If you get 1 or 2 ppm, that may well be meter accuracy, but over that - reject the tank. I think that the Sensorcon CO alarm at $129 is worth its cost as it's good for at least two years before servicing.

Scubaboard apparently redacted your "this $29 unit could work ok" suggestion - could you repost?

More and more portable units are being offered these days so the possibilities are increasing, but you do have to check the specs. Ensure that the unit reads in the 0-10 range, has 10% accuracy, etc. If you search Walmart for SMART SENSOR Handheld Carbon Monoxide Detector, you'll find a large number of units offered by various distributors in a wide range of prices from $27 & up, but if you try to buy one - most are out of stock. Supply chain issues in China I suppose. This one claims to be in stock with free 3 day delivery for $36: SMART SENSOR Handheld Carbon Monoxide Detector Meter

Now the Smart Sensor uses AAA batteries, and I hate that as they carry so little power and anything built to use AAAs probably could have been built to use AAs at least, but just carry plenty of extras. I would certainly write the date of purchase on the unit and discard in electronic recycling after a year, as I would not trust it longer than that nor try to get it serviced when new ones are so cheap.

Amazon seems to have a better stock of SMART SENSOR Handheld Carbon Monoxide Detectors and some are cheaper than $36 with free 3-day delivery, so check there too. I'll add a photo below to illustrate the unit.