I used 2000psi off the first then another 1000psi off the second.....for a total of 3000 psi mas o menos.
This is not normally how this is done, what if you would have used your 2,000 psi then went to your other tank to find you can not access its gas?
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This is not a slam but this is very poor gas management.
Now I am at a rock and a hard place, do I post or do I not post on what is wrong with this picture and how to do it safer.
If I do you may switch and have better gas management, if I dont' post hopefully you'll seek additional training and learn on your own, but I don't think that will happen.
The odds are good that regardless of what is said, he will do it again without seeking more training unless it is made obvious that he needs more training.
For a properly trained diver using independent doubles, the normal approach is to use 1/3rd off the first tank, switch to the second tank, use 1/3rd of it, then turn the dive and remain on the 2nd tank until you have used a total of 2/3rds of it. Then go back to the first tank to use a second 1/3rd from it. This leaves 1/3rd in each tank as a reserve and it ensures that when you turn the dive after using 1/3rd from each tank that you still have 2/3rds in both tanks so that either tank will be enough to get you back to the surface and/or your first deco gas in the event that you lose the contents of either tank.
As a rule, you plan the dive so that if you lose the contents of one tank or your deco gas that you have enough gas in the remaining tank to safely finish the dive. Since you have already "lost" the deco gas you did not even bring, you have to plan the dive to do the ascent and all the deco on 2/3rds of one of your tanks.
This means that you have to take deco into account and will need to turn the dive earlier to ensure that the 2/3rds gas in either tank is enough to get you safely back to the surface not just to the first deco gas.
The other issue here is that you may need 2/3rds in one tank as your buddy may need to use the entire 2/3rds of the other tank - especially if they are on a single tank and suffer catastrophic gas loss. What is less obvious is that each of you have to ensure that you have enough gas to support yourself and the heaviest beathing hoover in your team back to the surface - so the gas planning does not take your SAC/RMV into account but rather the SAC or RMV of the biggest air hog on the team. Ideally, if all the members of the team are properly configured and plan properly, all of you could suffer the loss of the contents of one tank and still surface safely and one of you could suffer multiple failures and lose everything and still surface safely.
In contrast when you have a single tank diver in the water on a deco dive with an inadequate reserve and /or when you are using faulty gas planning where you are not really using a redundant gas configuration, you are only ONE very small failure away from a tragedy. It is literally the diving equivalent of Russian Roulette.
So for the love of God if you are going to keep doing this, recognize there is an awful lot you do not know and do not control, get some deco procedures training, use proper configuration, proper gas planning, proper bottom and deco gasses and then pad it a bit with some rudimentary safety precautions like a deco tank, a stage bottle, a deco tank hung beneath the boat, etc.
To those who think that 200 ft single tank dives on air are ok as it is about nutts and that being willing to risk your nuts is some sort of noble or herioic act (as opposed to just being stupid) - consider that it possibly noble and herioic to risk your own nutts, but nothing ever gives you the right to risk other people's nutts by luring them into a situation where you potentially cannot get them out or by causing them to emulate your example while not truly understanding the risks they are taking. That is just plain socially and morally irresponsible.
