Hi Kevfin. I spoke with rangers on Monday morning and they informed me that the area is public use with no limitations: swim. fish, kayak...diving with scuba gear is allowed. The problem is getting to the pool: it requires special passes, fees, insurance, etc. to bring a private vehichle into the park. The alternative is haul the gear in on our backs (and those of a few volunteer sherpas) about a mile and a half from the parking lot to the pool. I didnt ask them about the underwater characteristics of the pool though. I was told by other visitors that it's at least 15 ft deep with a lot of crevasses and overhangs. From the surface, viz appeared to be 10 ft or better.
Cheers!