My buddy and I got our doubles filled with Trimix 20/18 and went to explore the deep shelf at Sledgehammer, located at Lake Crescent, Washington. We finally located the deep shelf at 206 feet of fresh water. The water was so clear that I could still see the sun above me.
We couldn't get 50% nitrox for deco, because everyone was out of oxygen in our area. Instead, we opted to plan the dive as if we were doing our deco on back gas (TMX 20/18) and then do our actual deco on 32% nitrox because it was what we could actually find.
30 feet for 2 minutes
20 feet for 18 minutes
We also did another 5 minutes shallow after we cleared deco just for another margin of safety. Total run time was just shy of 42 minutes.
The little flashlights that Bryan sells didn't leak, and I am not even sure if they are rated for 200 feet. I thought that was cool. Those things are tanks for being so small.
The deepest I've personally been on air is 170 feet. Putting helium in your mix is like night and day. I've never been so sharp so deep. It's one of those things that you truly get once you have been 8/10 narced and you switch over.
Really, the only problem up here is that lots of shops have gone belly up, and there just aren't a ton of divers anymore. Finding oxygen and helium is a real issue. My doubles will be sitting at the only "local" shop that does mix (1.5 hours away), and it takes a week to get enough helium to fill them.
I feel like diving up here is dying a slow, awkward death due to lack of demand. I really don't want to turn my garage into a Vance Harlow book, but I might have to if things get much worse.
Anyway, great times on the 4th of July.