Yeah, adding in a chiller makes things way more complicated than just adding a resistive heater. A decent looking chiller for an aquarium is ~$1,000, plus you need temp sensors and control wiring to maintain the setpoint properly, and then you need to pray the electricity doesn’t go out. A 1/3rd HP chiller draws around 1kW including the circ pump
An aquarium backup battery for a simple pump is like $50 for something that'll last a few hours of outage, but for a chiller with that kind of draw, it's a bit more expensive.
Yeah, you’d need a 1500 VA UPS to back it up, plus a decent amount of batteries (I don’t know the math on those, someone else figures that part out for me haha)
Aquarium circ pumps can probably be powered directly by 12VDC? That would make sense if it’s only $50 for battery backup.