As a diver myself, I'm stunned at the ingenuity of this experiment. I would have almost certainly built a steel pressure vessel with a viewing window on land and then used an air compressor to drive it up to 5 ATM, utilizing some sort of electrical igniter to start the flare without using the striker. All of that would have easily taken 10X the time and expense of simply diving down to 130+ feet with a plastic water jug, as you did! Impressive!