You may also get away with your own DIY
chiller. Start with a WalMart style 12 volt electric 'beer" cooler with 120vac adapter. Then buy about 50 feet of thinwall nylon/kynar/styrene tubing one size up from the hose that your canister filter normally uses (guess 3/4"ID
7/8"OD tubing versus standard 5/8" ID
hose on your canister filter). Drill two holes right through the cooler's flip-up cover which are just large enough to allow the tubing to pass through. Coil up about 40ft of the tubing inside the cooler, poke the two tubing ends out through the holes in the cover, and seal the tubing to the cover with silicone to prevent air from leaking around the tubing. Connect one tubing end to your canister filter discharge, and the other tubing end to your tank return piping. Put enough water in the cooler to submerge the tubing (you may need to use plastic tie-wraps to hold the tubing coils together rather tightly), and plug in the 120vac adapter.
You could also try this with garden hose or standard PVC
tubing, but the risk is that the thicker tubing walls will insulate your tank water from the cooler's water too much. You can also use multiple coils of smaller diameter tubing, as long as the cross sectional area of the multiple tubes adds up to something which exceeds the cross sectional area of your canister filter's standard hose by say 33-50%. The multiple coil approach with smaller tubing does reduce the effects of the tubing material insulating the tank water from the cooler's water though, but it gets tougher to fit all of that tubing in your cooler !
This will still only get you about 50 watts worth of thermionic cooling, but it might be enough to get your water temp back under 80 degrees. You can also give your DIY
chiller a 'boost' by adding ice from your freezer to the cooler's water every so often.