I was there yesterday. I did 2 dives, the first deep and the second shallow. The vis was great from the top to the bottom 20'+ everywhere to start with. The first thermocline was at 19-20'. With the water being high in the quarry, the bottom around most of the attractions is about 23-25. It was 69 degrees at that depth. The first dive I was fairly well dressed for cold water but the second dive I didn't wear a hood or gloves, My hands and ears were uncomfortably chilly if I was close to the bottom of the shallows.
The vis deep was better than it was shallow but it seemed to be darker than normal. My light was on my harness but I hadn't really planned on using it, when we hit 70', I unclipped it and turned it on. The deepest we went was the deep training platform, 89' according to my computer. The vis there was 30'+. It was 44deg there.
The second dive was something that I was unprepared for. They were having a treasure hunt. I had never done one, so I thought WTF. All of the balls were in the shallows. When 60ish divers all hit the bottom at the same time the vis went from 20' to about a foot! You almost need to be solo certified to do that because you chances of staying with your buddy are slim. I would say at least half of the divers, including me, lost their buddies. At one point, me and another diver swam into each other before we saw each other. On a plus note, I found a ball and won a nice dive watch.