I would recommend Pacific Coo 1/2HP as I am using it currently. Reliable & ability to support your aquarium size & beyond. Kick-in less often thereby saving energy costs.
Never ever put chiller outdoor cos' the rain, the sun, the dust & not forgettin critters of all sorts will do serious damage to the equipment.
Waterproof ? I surely give it the benefit of the doubt !
I am using the controller together with my MACRO CR. Cost is reasonable & also Good Quality stuff...readings are fairly accurate to date.
I sure do recommend this device for any budget conscious reefer.
Enjoy !