Pacific Coast CL-280 or CL-300. They're both 1/10th horse chillers and perfect for a 75g tank. The 280 has a single controller and the 300 has a dual controller for both heater and chiller. We probably sell more of that chiller than any other, and they have a very positive performance record. They're quiet too, like a very small window air conditioner. If PC doesn't seem like your thing, you might consider the JBJ 1/10. HTH.
