I ran a chiller many years ago until it stopped working. It was useful only on the hottest days of summer but you really need to size it for the tank and the amount of cooling you'll need. For this summer I'll be using the trick of RO/DI ice cubes in the tank or maybe zip lock bags of ice to cool the 65g tank down. Hopefully when the 135g is running in the basement it will stay cool all by itself.
135g Main Tank/ 125g Frag tank with 55g sump.