Chiller will stop the problem and help maintain the water temperature at a preset level, but expect increase of electricity consumption equivalent to 1 hp air condition. But if you are living in a country with 2 season, u will need them during winter.
Some ppl i saw, using plastic bottle freeze in the refrigerator top compartment, then put them in sumptank so tat the water get chilled. They put alot of those, so taht when the tank temperature goes up, they put 5 tube into it, then another 5 tube as standby. It's kind of troublesome but this is the most economical way to help adjust the water temperature.