In late 2008 we bought a brand new house and built a brand new pool (our first) to go with it. Life was great, loved the pool, until about July 2009. By then taking a "refreshing" swim felt more like getting into a hot tub. I would actually start sweating being in it. By the end of July the water temperature had risen to 95 degrees. No one wanted to go swimming and why would they. This was unacceptable. No swimming during the winter cause it's to cold, and no swimming during the summer cause it's to hot. How depressing. Why even have a pool. Time to hit the Internet. The first thing I looked at were compresor pool coolers, similar to what you find in an air conditioner. They are very expensive, expensive to operate and maintain and are not very effective. My search eventually lead me Glacier Pool Coolers website. These do not use freon compressors but a cooling tower that works exactly like the radiator in your car. Water is distributed over the top of the tower which is filled with baffles. A large powerful fan located on the top of the tower sucks air up through the tower cooling the water as it flows down the baffles. These systems are also known as swap chillers. Given that I live in a humid climate (Houston Tx.) I was very skeptical as to how effective this would be. Glacier told me that their GCP210 unit would cool my water down at least 8 degrees even on the most humid days. I was frustrated and desperate. I bought their sales pitch and their GCP210 unit. By mid August the unit was installed and running. By then my water temperature had reached 98 degrees. After the water passes through your filter it's diverted to the chiller then back to the pool. Because your pump supplies the water, the chiller only runs when your pump does. As you can imagine, it takes a while to cool down 25,000 gallons of water 10 degrees. But after 24 hours my pool went from 98 to 90 and after another 24 hours it was down to 84. I was ecstatic. This thing work far beyond my expectations. It's now been 6 years, with some VERY hot summers and my pool stays between 82 and 87 degrees even on the hottest days. So, what are the cons of this system?? It's big. It stands almost 6 feet high and is about 4.5 feet in diameter. Also the fan is pretty loud. But that's about it for cons. Operating cost are minimal as there is only a fan to run. As for maintenance, it has consisted of lubricating the water distribution rotor with siliclone before and after using it each summer. Some hints to get the most out of these coolers. If possible install it where it's shaded. Also, I run my pump from 4:00 PM to 10:00 PM to take advantage of the relatively cooler night temperatures. Also, don't wait till your pool is hot to start it. Once my pool hits 80 on comes the chiller. It's funny to hear my wife complain that the water is to cold when I do this. BTW, I am not affiliated with Glacier in any way, nor am I getting anything from them for this. I simply wanted to pass along a very good solution for anyone that hates jumping into a pool that feels like a hot tub.