I'll try to answer your question rmkleman. The bottom aerator I have definitely eliminates the cold spots in my pond by mixing the water from bottom to top. I don't have cold spots but the water is pretty much all very cool and maybe even a little too cool for some to swim in even with the warm spell we've had. Without the aerator on, the upper 2 to 3 feet of my pond would be in the low 80s right now while the bottom layer would be in the low 50s. 80 degree water is comfortable for swimming and 50 obviously is not. By mixing the water the temp is somewhere between but pretty uniform top to bottom.



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