Congratulations on getting your water back to clear--great job!

I wish I could help you with the nut grass, and if you find a solution that works, by all means post it here. I have an 1100 gallon koi pond next to my pool and am forever spraying the nut grass that grows up through the rocks around it. When they installed the pond they put down a very thick (1/8" or so) black matting under the liner, and so far the stuff hasn't grown through it, but it grows around it like crazy. Don't know what to do other than keep spraying it at the surface, but I know that's not doing anything for underneath.

As far as cooling your pool water, you might want to consider a fountain of some sort and running your pump at night. Here in Louisiana we're getting the same temps/heat index you describe, and my pool water currently is at 94 degrees--feels more like a hot tub than a swimming pool. We keep the slide running during the day while the kids are in the pool, so it's getting cold water refilled from the house and it does a fair job of dropping the temp a little, but aerating the water at night will help cool it off a little, as well (watch your pH, though, because it will rise due to the aeration).

Janet