Narcotic effects from air become too great. From 30 m He blends are advised. Effect of gas density on work of breathing also is starting to reach an undesireable level.
Christopher is right, we write the MOD on the label as the Max operational depth depend on more than just the PPO2 of the oxygen content in the gasmixture. The Gasdensity and Narcosis effect also play a role. I might do a video on oir standard gasses soon ;-)
Thanks for the reply’s guys. A video on it would be great. All the teaching material is pretty simple when it comes to calculating MOD and doesn’t always take into account gas density or narcosis effect. Apps like Nitrox Buddy for example are pretty rudimentary when it comes to giving you your MOD.
You really should calibrate your analyzer with dry air, not wave it around. Humidity can add percentage points to your measurements. The reason you calibrate is so you don't pick up the humidity in the air, and your readings are accurate. For normal EANx mixes between 20 and 40% (like EAN32 or EAN36), single point calibration is good enough. You calibrate only on dry air, and your EANx measurements are pretty accurate. For higher oxygen mixes (over 40%) it is a good idea to do a two point calibration (if your analyzer allows it). You should calibrate on dry air, and on 100% oxygen. For hypoxic trimixes, you should do a three point calibration. In that case you calibrate on dry air, 100% oxygen, and 0% oxygen (like 100% nitrogen, helium, or argon). Calibration sets base points for the gas mix curve. At the extremes there is more deviation if you don't calibrate, that's why you also calibrate on 100% oxygen for high oxygen mixes, and on 0% oxygen for low oxygen mixes. I wish you would've showed how the flow limiter worked as well. You can crank your valve open completely when using a professional flow limiter. It will automatically adjust to provide just enough flow to analyze your gas. After you've analyzed your gas, close your valve, and use the bleed screw to release the excess pressure in the flow limiter. You can also wait until it's bled the excess pressure through the tiny pinhole, but that can take some time. Your electrochemical oxygen sensor has a limited life span. Depending on the flow rate needed by your analyzer, and the number of times you analyze, the life span can be anywhere from 6 months (high flow/almost daily use) to 3 years (low flow/rarely used). A new oxygen sensor is around 100 dollars/euros. Even if you don't use the analyzer, the sensor will need replacing every few years. If you have a trimix analyzer with a thermal conductivity helium sensor, you'll need to replace the sensor every 5 to 10 years. That one's around 300 dollars/euros. The Divesoft He/O2 or Solo analyzer uses a solid state helium analyzer, which measures timbre shifts in sound. That one never needs replacing. The Divesoft analyzer is a little bit more expensive than most trimix analyzers, but you'll reclaim that extra cost the next time you would need to replace the thermal conductivity helium sensor.
I have a question about my set up i would like you to ask. Can i contact you somewhere? Where i can send a picture to show? Its about my doubles and hoses.
