SNIP My eyes roll when divers claim they don't need CO tank testers because they only get air from dependable shops.
Don.
Eyes rolling or not. They are right.
Sadly your suggestion of a CO detector would have been of little use in this situation.
Frankly in this case the OP clearly doesn't need a CO detector it would have simply overlooked the problem and IMHO made things worse.
An electronic CO detector would have made no difference in fact I would go further and say that it would have been hugely detrimental. CO detectors are not the answer.
Both to the OP and all other divers as it would have given a false sense of security.
In this situation and case he and others would have been duped by the zero CO reading displayed and more seriously duped into thinking there was nothing wrong with the cylinder/tank contents.
Further
1. He would have not necessarily made the connection of his headache and being dizzy with contaminated gas, After all if he had used a fancy CO analyser that would have showed all clear.
Further if he or even had the dive shop used one then both would have been duped.
2. He would not therefore have seen the need to contact the dive shop to discuss or indeed have necessarily have contacted the second dive shop for a VIP inspection
3. By now if he had indeed been using this CO detector he would have put his headache and dizziness down to bad food or a sick day, nothing more and we wouldn't be having this post.
By contrast and comparison my suggestion of a simple smell test even without the $60 visual indicator and the problem would have been revealed to all.
All divers should invest in a nose with two nostrils and a tad more free education.
Not a battery driven CO detector even with the lights. For that just buy a torch. Iain Middlebrook