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I have no idea what this means.

I led a dive trip there, and I assume we are talking about the same operation. Their policy was that when a diver got down to 1,000 PSI (still plenty in a 100 or 120 cubic foot tank), that diver would continue on the guide's long hose until a second diver got to 1,000 PSI, at which point the...

As people keep pointing out in this thread, it violates Dalton's Law. So what do we who do not have major scientific training do? We have to look for support from people who do have such training. if someone is going to make a claim that appears to violate Dalton's Law, that would be...

Powell did extensive research before writing Deco for Divers, including talk with Michael Powell, formely Doctor Deco on ScubaBoard. Jablonski and Georgitsis were firm advocates of the oxygen window theory being cited here. It took a lot of evidence for them to publicly admit they were wrong...

Yes, you did. And since then there have been multiple posts explaining that pretty much all authorities have determined that the theory you explained is not valid. It has been pointed out that it violates Dalton's Law. What you need to do is explain why all the people who have decided it is not...

The concern with sharing air and continuing the dive assumes that the receiver is empty or near empty. If the diver still has lots of air but is just sharing air in anticipation of running out later and thus ending the dive early for everyone, it isn't all that dangerous. Years ago I dived with...

When I saw this post, I thought I knew the answer, but I actually don't. I assumed these sites were officially linked to the agency, and I figured it would cost way too much to have dedicated employees from such a large agency answering questions. Then I looked at threads in the SDI and SSI...

The water temperature at both Chatfield and Aurora Reservoir is currently listed at 52° F. Better bring your drysuit.

You do need to have some sidewall to use that technique. That's why I had to use the top of the blade method with the Atomic split fins, as described in my last post. I first saw a video of this technique when I was with a tech student, a college professor. I did not see how the tiny surface...

Absolutely. I learned the second method mentioned above exclusively at first. When I learned the first method mentioned, I switched to it. Quite a few years ago, I taught a pool refresher class to a father and his teenage son. They arrived with their gear, and as they were setting up, I looked...

Much more than several years ago. I was a Jet user for years, but when I became the tech instructor for a shop that did not sell ScubaPro nearly a dozen years ago, I had to switch to a brand they sold, and that put me in Hollis F-1s. They were easily a match for the ScubaPro, including in...

Some cases are not intentional. An interesting experiment done decades ago indicates that personal bias can come through even when honestly trying to appear objective. Teachers were told to conduct an experiment in their classrooms in which they showed students pictures of random people and...

You should get good advice, but I want to give a caution. I worked for two different dive shops, and here is why I left the first one, which I felt was otherwise excellent. They switched dive training agencies, and the owner of the agency they went to came in and did a week-long workshop (which...

There are indeed several types of fins on the market, and it is hard to know what is right for you. I first started diving more than a quarter century ago, and I bought fins immediately (Cressi Frogs). About 4-5 years later I decided I needed newer technology. I sold those first fins and got the...

I would like to make an observations about multi-step safety procedures in general, and I would like to start by talking about something not remotely related to scuba. When I first became involved with scoring student writing assessments, we were given a scoring guide that was incredibly...

I am not clear on the point of posting these articles. An explanation would be nice.

It is easy to point at something as the reason for an existing situation, but that is a fallacy. Yes, fishing may be a factor, but there are others. If you are missing pelagics, it may be more because the prey they need to eat is not there in sufficient numbers. That can be caused by the extreme...

Yes, indeed. The fact that technical diving is more dangerous than NDL diving is emphasized in the tech program I taught, all for the purpose of making sure the divers took the training seriously.

I understand all three laws, but I have no idea how what you wrote here explains why this theory, which has been dismissed as inaccurate by everyone in authority for about 15 years, is actually valid.

This is exactly what I wrote about earlier. That theory is a violation of Dalton's Law, as Mark Powell wrote in Deco for Divers. The theory was the basis for the GUE and UTD S-curve ascent profiles. Both agencies later determined that the science behind it was not valid. I read the paper on...