The last year sampled in the graph you cited for Austin shows it at about 0.25ppm. That's closer to the 0.1ppm I cited then the "under 1.0ppm" that you cited.
Ignoring the weeds for a moment, what threshold do you use to reject a tank? I haven't gotten an analyzer yet ( I probably should have when you put the ScubaToys deal together last year ) but if I did get one, it's kind of important to have a threshold otherwise why bother?
Yeah, I guess so for averages. Calibrate a tester on a known to be clean tank sometime while standing downwind of I-35 when it's full, then tank the flow resistor off and check the wind and I bet you get a much higher reading - more like 3-5.
Not a big deal really, but a trend.
Ignoring what weeds? I did not put together that group buy, and I talk about the need for testing so much that I certainly don't want to get involved with any actual sales at any level, but it was a nice one. Diverightinscuba.com has the Analox for $352 & free shipping and your LDS may well be willing to beat that, and there are other brands.
This guy came up with an interesting kit involving a little DIY work, altho I know nothing about the model or company - still, looks appealing.
http://www.scubaboard.com/forums/co...relatively-inexpensive-co-detector-setup.html
This just posted today for sale here, new but the sensor may be a year old - I can't read the manufacture date in the pic? Keep in mind that a sensor is good for 3 years or so, and run about $150, so make sure they are recently manufactured when you have to replace:
www.scubaboard.com/forums/classifieds-computers-gauges-watches-analyzers/460381-new-analox-carbon-monoxide-analyzer-suunto-guage-set.html
What cut-off threshold? That's a personal call and as I've said before, pick a number between 3 & 15 and stick to it.
I wouldn't dive over a 10, but many won't go over 3 - and there should not be any anyway!
I'll dive with 1 or 2 ppm CO in a tank, but I prefer none. Last month in Aruba I rented a tank with 4ppm. Took it back and tested until I found a tank with 2 ppm. The guy at the shop said they're allowed up to 6 ppm CO in a tank.
How interesting. Was the 6 a government limit or a shop standard? The Dutch Indies have been dickering over independence from The Netherlands and I don't think any of the islands can agree on details - none cutting the apron strings completely. Did they have an inline monitor or a tank tester of their own?