I believe the supposition that buoyancy is high in Bear Lake is BS. It is VERY unlikely it is as high as normal salt water, so the kid was still overweighted a LOT. Even if it were like the Great Salt Lake, which is NOT likely, the kid was still overweighted. You can look at all the formal geological and limnological doscuments for Bear Lake and anamalous buoyancy is never mentioned. The mineral load in the water is mentioned, but it is nothing special, and would not likely cause any noticable buoyancy effects to a diver.