I am getting prices on 3 different types of shade cloth. White at 50 % shade, black at 80 % shade and aluminized at 80%. The salesman told me he had a customer use the aluminized and had over a 10 deg. drop in his greenhouse. I only intend to cover 2/3s of the surface and have it suspended 6 to 8 ft above the water. I just need to find out how hard my wallet will be hit with the 3 different types. I only have a small spring feeding my pond and when we have a drought it quits flowing. My pond used to leak down to 10 ft deep but I had that fixed when I drained it and covered up a gravel seam that the original excavator guy left open with straight wall sides. This other guy who sloped my banks said my idea would not work and my pond was leaking else where, but I proved him wrong after I had him do what I wanted.
I also wanted to get a fountain aerator to run at night when temps are cool as I know this will help cool the water. There a company that makes these water cannons for swimming pools to cool the water down when it gets too hot by about 10 deg. and they are run at night, but they want over 3k for those things. Well I guess I will give this a try as long as it is not too expensive.