I assume you tried fans? I was surprised by how much one 15 cm diameter fan cools my 250l tank. I have it hooked up to a wifi-controlled outlet. There is of course quite a bit of evaporation, but an ATO is a lot cheaper than a chiller.
Fans can be very helpful, and the heat can be managed with a bit of help from the A/C in the hot days.
However, as someone that comes from a hot country in the Middle East, all you can really grow in a tank under these conditions are softies, and even than - almost everyone I know, including me, ends up cracking as we see the temps rise on the very first summer and runs in an emergency to purchase a pricy chiller.
I’m confident that Australia will be under the same heavy heat conditions as in my area, if not more, and I would highly suggest not to wait for an emergency to occur, but to be prepared with a solution beforehand, because then you can take the time and find a good deal instead of being pressured to buy anything that’s available for you to purchase at that moment.
If I may add a quick personal frustration here - I’m so jealous of you guys that are able to randomly spun up picos or grow phyto. You have no idea how many times I wanted to do something like this and than realized it’ll be impossible to keep in the summer without spending a good chunk of money or ridiculous engineering efforts just to keep it cool.
It was long ago when I was reading threads on this but as I recall one snafu is that refrigerators will add heat to the ambient air. So unless the unit is away from the tank, you are sorta spinning your wheels.
So perhaps doable given fridge location, ambient temps and the amount/rate/area of water circulated
Yup. Both chillers and refrigerators would heat up the room while cooling the tank, though a chiller would have far better heat transfer efficiency, and this would throw a lot less heat into the room.
I would actually advise against running the fridge far from the tank, because the longer the tubes are - the more heat it will absorb in the way back to the tank, possibly making it insufficient. One could try to work around this by insulating the tubes, but I’m not sure how much that would help.
Another thing to consider here is the contact time - tubes that just go through a fridge may not have enough surface area to make a significant difference, so I would consider having a good amount of extra tubing inside the fridge, or even a container the water goes through to increase the contact time.
