Water Temperature Comparison

I'm filling the pool to how high I want the final pond level to be because I built a temperature reader (pvc pipe with aqua thermometers duct taped to various depths) and I want to get an accurate reading of just what my range is. Right now, in a depth of about one-and-a-half feet, I have a temperature (at three inches and on the bottom) of about 83 degrees with a half a degree variance. That's a bit hot for a 'slider, so I'm going to have to make sure my shade plants cover at least half the pool and I'm going to have to make sure it's ok at different depths.

I just checked on average water and air temperatures for Lake Mead and then my part of the city, and the air temp status were only different by a maximum of six degrees (but most of the numbers were only three or four degrees difference). The water temperature at three feet of depth out at Lake Mead (with no shade plants and no wall of shade in the morning) might just be an accurate reading of how I could expect my pool/pond to be. Mine should even be a little cooler because I'll be constantly adding water and I have shade plants.

The lowest the water temperature on the list would be 55 degrees, and that's in January and February. I could get a heater and put it at the bottom of the deepest part and I'll bet I could keep my water temperature at closer to 60, which means my 'slider won't hibernate. He may be a little cold, but he won't hibernate. And it will be ok for my goldfish too, provided the turtle doesn't eat them all. Because he might. Greedyguts.