Quote: (Originally Posted by
Tino Corp.)
Hello Dave,
Can you please explain me how you would apply you method of lowering the PpO2 on a KISS system where there is a continuous flow Am I missing something (or is it just that I am still asleep)?
Yes, you're missing that on/off valve on the 02 bottle...... it turns ON. It turns OFF. Th cylinder is upside down so you can USE IT. So do!
I have a 90 degree ball valve right at the KISS valve on my KISS to make it easier. It's off on descent and until the loop is where I want it *if my dil is hot* (which normally it is NOT). Remember, that I am not suggesting that we deliberately MIX a hot diluent, but only that we use a normoxic one until we are FORCED to do otherwise. MOST of the diving you will likely do will be OK on a 21% dil while still allowing normal 02 flow on descent, It's only a small footprint of depths (especially on a KISS where it's depth limited anyway) where securing 02 flow on descent is a technique that should be considered.
With all due respect, and I mean this sincerely: There is a REAL PROBLEM in training if KISS Instructors are not teaching how to lower PP02 in event of some sort of high PP02 state being reached in a KISS, and with manual additions being the norm, and a mis-managed manual add being the normal way to overshoot desired PP02, this is a normal drill for the KISS diver trainee (or ought to be). I'm surprised that any KISS diver would be sent forth "trained" without the knowlage of this. Shame on the instructor, not the student.
I'm going to reiterate this once again: Use of low fraction 02 diluents *when not absolutely required* is a really dumb technique. If you have to because that's all the gas you have in micronesia, then we do what we need to do. But in the first world, where gas is available, there is NO REASON to do so. For a 500 foot dive? Do so! For a dive to 200 feet? It's DUMB. Use the right tool for the right job.
Dave