I installed my pool coolers on my returns tonight and I must say so far so good. As soon as I installed them I turned the pump on and jumped back in. The water spraying back into the pool is about 10 degrees cooler. You can put your hand in the water and then stick it in the spray and it is day and night difference. It was very refreshing as I was swimming my laps to swim past the spraying water. Unfortunately, I have algae starting to develop in my pool so I shocked it and put my Aquabot in. I am leaving the pump running all night with the coolers attached. My water was a yucky 91 degrees tonight, and we have nothing but 95+ days ahead with heat indexes of over 100. I am hoping to get it under 85 degrees. Now I have to kill the algae!