WarrenZ
The Ultimate Bad Example
We all want to be safe divers and we have all heard about getting bad air or checking your tank for bad air, when I was going through my open water course we were told to smell and taste the air for any off putting smells. However unless the tank is grossly contaminated there may not be an odor, especially when we are talking about the odorless, tasteless, and colorless gas carbon monoxide. After seeing a close call from contaminated air at a local spring and on one of my trips to Mexico myself and several of our divers came up from a dive with a headache and nausea I decided that simply tasting the air wasn't an adequate safety measure.
Carbon monoxide or CO causes headache, dizziness, weakness, nausea, vomiting, shortness of breath, impaired judgment, confusion, unconsciousness. It is important to note that CO bonds to the red blood cells preventing them from carrying oxygen throughout the body and that it is an accumulated effect so the longer you are exposed the more risk you are at. In the US the limit for CO in scuba breathing gas is 10 ppm and in the UK the limit is 3 ppm.
When I decided to start testing my own tanks for CO I originally thought I could just buy a battery powered CO detector from the hardware store and throw it in a bag filled with tank air. Unfortunately as I found out most Home CO detectors won't even detect less than 30 ppm and won't alarm until the concentration of CO is over 70 ppm for several HOURS! Eventually the solution I found was a Sensorcon CO inspector which is a handheld CO gas analyzer typically used by home inspectors, miners, and HVAC techs. I had been using this tester with my OMS O2 test kit using a “T” fitting on the hose from the regulator to my O2 tester. If you try to feed the CO Inspector directly the pressure of the gas being tested would overwhelm the sensor and you would get bogus readings unless you give the excess gas somewhere to escape. The test set worked as long as the test kit was stationary or the hose to the CO Tester would pop loose. I knew there must be a better solution so I kept my eye out for one.
What I found was DiveNav’s cootwo a combination O2 and CO tester which took some of the great features of their NitroxBuddy analyzer and app and improved them. For the uninitiated the Nitroxbuddy is a nitrox analyzer which uses the Nitroxbuddy app on your smartphone as its display. One thing I was looking for was in a combo analyzer was that it could function without the app or my smartphone as I may not have either available on the boat. So when I saw that the cootwo was going to have its own LCD display I decided to get one. DiveNav was listed the cootwo on Kickstarter and it surpassed its original goal in days. As I was getting closer to a trip to Curacao and I knew that the ship date for my cootwo from the Kickstarter release would be after my trip I contacted DiveNav and asked to take one of their test units with me. Believe me when I say DiveNav is a great company to have dealings with, they hooked me up with one of their cootwo DELUXE kits and told me to “have fun with it”.
So here's what you get with the Deluxe kit: a molded plastic carry case with custom cut foam containing the cootwo tester, the BC low pressure adapter, and charging cable. The BC Adapter pops over the end of the cootwo and is held in place by and oring on the body of the cootwo. It is important to give this oring a little lube otherwise it can be a bugger to get the adapter off later. The low pressure adapter I received was the standard BCD fitting but should be able to be adapted to an airsource quick connect with an adapter.
So being a guy I didn't even stop to notice that there wasn't an instruction pamphlet included but I was assured that DiveNav is working to get their online tutorials completed as the production model cootwo ships. However I quickly paired the cootwo with the Nitroxbuddy app the cootwo only has one button so not much could go wrong. The first thing I noticed was the cootwo prompted me to calibrate the O2 sensor. This is accomplished through the app by selecting the 02 concentration you will calibrate with and then exposing the cootwo to that known concentration of oxygen, easy as that. However I usually was doing this without the smartphone as I hate carrying it around with me on the boats. Calibration in standalone mode is done by turning the unit on and pressing the activation button for longer than two seconds. The unit will start flashing “O2 ?” and “CAL ?” you then press the button again to confirm you are wanting to calibrate the O2 Sensor the screen will display O2V and the sensor voltage in MV. You then hold the unit to an airsource for 30 seconds until the display goes back to showing the O2 percentage. The standalone O2 calibration is limited to 24 hours while the smartphone calibration is programmable from 6 hours to 48 hours.
I also decided to test the carbon monoxide sensor which can be calibrated through the smartphone app with a CO calibration gas of up to 20 ppm. Unfortunately the calibration gas I had on hand for testing and Cal of my other sensor is 50 ppm so I quickly found out that the cootwo’s CO sensor tops out at about 40 ppm which in more than anyone should be diving with. Since I did not have a Co cal gas that is within range of the Calibration function in the app. I am still using the factory calibration for CO which is good for 12 months. The displayed CO value blinks above 3 ppm and the LED blinks above 5 ppm.
So out came the old analyzer set for a head to head test which showed that the cootwo was at least as accurate as my old method and much more fun since the app gives graphs and automatic data logging right on your smartphone for those inclined to hoard that type of data. It also gives a nice clear reading on its LCD if you are not using the app.
Since the cootwo’s carry case is not waterproof and I do not trust any place on a boat to be dry enough for electronics I packed the cootwo and its BC adapter in the small sized pelican tool kit I carry on trips but as you can see from the photo it could hide just about anywhere. Once I got on the boat I had to do a stand alone O2 cal and was off and checking tanks. The boats we were on had an Analox O2 tester and I am proud to say that the cootwo was just as accurate and would give a CO check with every nitrox testing. I also tested a couple of air tanks as well and never saw any CO the whole week. I was not surprised after seeing how well the dive ops compressor setup was being maintained.
Things I found I liked on the cootwo were: its small size, ease of use, standalone operation option, smartphone calibration options, and its battery life on the rechargeable battery was great (I charged it one night during the trip because I remembered that had not charged the cootwo when I received it). The BC Adapter allows you to test the tank you were going to use after you put your regulator on it to verify tank contents or the adapter can be pulled off and the cootwo can be held to a bare tank valve for testing of multiple tanks quickly. I also have to say DiveNav was great about answering my questions via email. I appreciate any company who works with divers to solve problems and to improve their products.
There was two things I didn't enjoy: There is no option to calibrate the O2 Sensor using ambient air; I am used to being able to take the hose cap off the sensor and calibrating to ambient air on my OMS O2 Tester but due to the nature of the cootwo it needs to have air flowing through the body of the cootwo to reach the O2 Sensor and using ambient non moving air would take too much time to get a proper calibration. I also had some trouble getting the BC adapter cap off with wet hands but a little tribolube on the oring and the cap comes off without too much effort. I was also told that leaving the BC hose connected gives a little more to grip when removing the cap.
It does not take much CO to become a big problem as depth increases. So as you get off the beaten dive path where Gas powered compressors that may or not have been properly maintained are more common it is up to you to ensure you have safe breathing gas. There are several SCUBA CO testers on the market that were not reviewed here however if you dive nitrox and are concerned about CO the cootwo is a great two in one unit. A little disclaimer I am not being compensated by any of the companies mentioned in this article all of the devices I was using are ones I purchased or have on order. I am glad to say the cootwo lived up to everything I was expecting of it. My thanks to DiveNav as a whole and to Alberto Mantovani for answering my questions so quickly.
Carbon monoxide or CO causes headache, dizziness, weakness, nausea, vomiting, shortness of breath, impaired judgment, confusion, unconsciousness. It is important to note that CO bonds to the red blood cells preventing them from carrying oxygen throughout the body and that it is an accumulated effect so the longer you are exposed the more risk you are at. In the US the limit for CO in scuba breathing gas is 10 ppm and in the UK the limit is 3 ppm.
When I decided to start testing my own tanks for CO I originally thought I could just buy a battery powered CO detector from the hardware store and throw it in a bag filled with tank air. Unfortunately as I found out most Home CO detectors won't even detect less than 30 ppm and won't alarm until the concentration of CO is over 70 ppm for several HOURS! Eventually the solution I found was a Sensorcon CO inspector which is a handheld CO gas analyzer typically used by home inspectors, miners, and HVAC techs. I had been using this tester with my OMS O2 test kit using a “T” fitting on the hose from the regulator to my O2 tester. If you try to feed the CO Inspector directly the pressure of the gas being tested would overwhelm the sensor and you would get bogus readings unless you give the excess gas somewhere to escape. The test set worked as long as the test kit was stationary or the hose to the CO Tester would pop loose. I knew there must be a better solution so I kept my eye out for one.
What I found was DiveNav’s cootwo a combination O2 and CO tester which took some of the great features of their NitroxBuddy analyzer and app and improved them. For the uninitiated the Nitroxbuddy is a nitrox analyzer which uses the Nitroxbuddy app on your smartphone as its display. One thing I was looking for was in a combo analyzer was that it could function without the app or my smartphone as I may not have either available on the boat. So when I saw that the cootwo was going to have its own LCD display I decided to get one. DiveNav was listed the cootwo on Kickstarter and it surpassed its original goal in days. As I was getting closer to a trip to Curacao and I knew that the ship date for my cootwo from the Kickstarter release would be after my trip I contacted DiveNav and asked to take one of their test units with me. Believe me when I say DiveNav is a great company to have dealings with, they hooked me up with one of their cootwo DELUXE kits and told me to “have fun with it”.
So here's what you get with the Deluxe kit: a molded plastic carry case with custom cut foam containing the cootwo tester, the BC low pressure adapter, and charging cable. The BC Adapter pops over the end of the cootwo and is held in place by and oring on the body of the cootwo. It is important to give this oring a little lube otherwise it can be a bugger to get the adapter off later. The low pressure adapter I received was the standard BCD fitting but should be able to be adapted to an airsource quick connect with an adapter.
So being a guy I didn't even stop to notice that there wasn't an instruction pamphlet included but I was assured that DiveNav is working to get their online tutorials completed as the production model cootwo ships. However I quickly paired the cootwo with the Nitroxbuddy app the cootwo only has one button so not much could go wrong. The first thing I noticed was the cootwo prompted me to calibrate the O2 sensor. This is accomplished through the app by selecting the 02 concentration you will calibrate with and then exposing the cootwo to that known concentration of oxygen, easy as that. However I usually was doing this without the smartphone as I hate carrying it around with me on the boats. Calibration in standalone mode is done by turning the unit on and pressing the activation button for longer than two seconds. The unit will start flashing “O2 ?” and “CAL ?” you then press the button again to confirm you are wanting to calibrate the O2 Sensor the screen will display O2V and the sensor voltage in MV. You then hold the unit to an airsource for 30 seconds until the display goes back to showing the O2 percentage. The standalone O2 calibration is limited to 24 hours while the smartphone calibration is programmable from 6 hours to 48 hours.
I also decided to test the carbon monoxide sensor which can be calibrated through the smartphone app with a CO calibration gas of up to 20 ppm. Unfortunately the calibration gas I had on hand for testing and Cal of my other sensor is 50 ppm so I quickly found out that the cootwo’s CO sensor tops out at about 40 ppm which in more than anyone should be diving with. Since I did not have a Co cal gas that is within range of the Calibration function in the app. I am still using the factory calibration for CO which is good for 12 months. The displayed CO value blinks above 3 ppm and the LED blinks above 5 ppm.
So out came the old analyzer set for a head to head test which showed that the cootwo was at least as accurate as my old method and much more fun since the app gives graphs and automatic data logging right on your smartphone for those inclined to hoard that type of data. It also gives a nice clear reading on its LCD if you are not using the app.
Since the cootwo’s carry case is not waterproof and I do not trust any place on a boat to be dry enough for electronics I packed the cootwo and its BC adapter in the small sized pelican tool kit I carry on trips but as you can see from the photo it could hide just about anywhere. Once I got on the boat I had to do a stand alone O2 cal and was off and checking tanks. The boats we were on had an Analox O2 tester and I am proud to say that the cootwo was just as accurate and would give a CO check with every nitrox testing. I also tested a couple of air tanks as well and never saw any CO the whole week. I was not surprised after seeing how well the dive ops compressor setup was being maintained.
Things I found I liked on the cootwo were: its small size, ease of use, standalone operation option, smartphone calibration options, and its battery life on the rechargeable battery was great (I charged it one night during the trip because I remembered that had not charged the cootwo when I received it). The BC Adapter allows you to test the tank you were going to use after you put your regulator on it to verify tank contents or the adapter can be pulled off and the cootwo can be held to a bare tank valve for testing of multiple tanks quickly. I also have to say DiveNav was great about answering my questions via email. I appreciate any company who works with divers to solve problems and to improve their products.
There was two things I didn't enjoy: There is no option to calibrate the O2 Sensor using ambient air; I am used to being able to take the hose cap off the sensor and calibrating to ambient air on my OMS O2 Tester but due to the nature of the cootwo it needs to have air flowing through the body of the cootwo to reach the O2 Sensor and using ambient non moving air would take too much time to get a proper calibration. I also had some trouble getting the BC adapter cap off with wet hands but a little tribolube on the oring and the cap comes off without too much effort. I was also told that leaving the BC hose connected gives a little more to grip when removing the cap.
It does not take much CO to become a big problem as depth increases. So as you get off the beaten dive path where Gas powered compressors that may or not have been properly maintained are more common it is up to you to ensure you have safe breathing gas. There are several SCUBA CO testers on the market that were not reviewed here however if you dive nitrox and are concerned about CO the cootwo is a great two in one unit. A little disclaimer I am not being compensated by any of the companies mentioned in this article all of the devices I was using are ones I purchased or have on order. I am glad to say the cootwo lived up to everything I was expecting of it. My thanks to DiveNav as a whole and to Alberto Mantovani for answering my questions so quickly.
