I was reading an article that talks about PO2..
Instruction: CNS Oxygen Toxicity | Scuba Diving
This point stuck out at me -
"Please note: There is no more danger with a 50 percent exposure to oxygen at 1.6 than there is with a 50 percent exposure at 1.4 or 1.3. It's the total dose, not the PO2 that determines your risk factor."
I called a local LDS and inquired about one of the dives for this summer - he said to the sand is 130ft so you would be diving 28% Nitrox - which is 1.38 PO2... Would I be allowed to dive 30% at 1.5 or is that pushing the limits?
The crew on the boat would take a dim view of a passenger diving a "hot mix" for the destination wreck. 30% wouldn't get you left at the dock for a wreck with enough relief that you could stay shallower - say the Stolt or the Algol - but we'd want to understand your dive plan and your determination to stick with it. Say you dropped a light over the side of the deck of the Algol at 100ft. Do you have the restraint to watch it go bye-bye... or are you going to chase it?