I spent the last five years battling Toronto's summer heat, with pop bottles with frozen water, calling my wife from work to check the temp, shutting of the lights early. This year I decided I no longer want to worry about it and grabed a PCI 1/4 chiller. It works great, much quieter than I expected. The only downside of it is the size of the chiller itself.
I would have liked to try one of the new Profilux Temp Control units but the price was a too hight for me.

i keep my AC at a constant temp ( both in the summer and the heat in the winter ) and have a basement sump that really helps keep the tank temp down.

I find running multiple tanks, at least multiple tanks with halides, pretty much negates the "This is Calgary" factor, basement or no. :( I would imagine that more sane people with fewer tanks have less of a problem in this regard.

I have an in wall air conditioner in my living room (where my tank is) but I've always had difficulty balancing the tank temp in the summer because like most in-wall air conditioners there is no real control. I have to turn it on or off manually. Which causes difficulties when I'm away.

Last year I got a little smarter and put it on a timer (to come on during the heat of the day and off in the evening) but that still isn't the best solution because the tank would get too cool when the weather didn't heat up the house.

This year I managed to find a plug-in thermostat and Canadian tire. I works great! I set the temperature and it comes on and off as needed. It was 38 degrees outside yesterday and the combination of the air conditioner and fan across the sump kept the tank temp steady at 79F all day.

I can't find a link to it but it's built by Noma and you can find it in with the light timers. I think it cost $25. It works so well I bought a second one for my portable air conditioner. I now no longer worry about the wicked fluctuations of temperature I get in my tank (especially when I'm away).

Cheers

Does it work with the portable? We finally broke down and got a portable unit but I am not sure that the thermostat timer would work.

We have no other air conditioner. My tank has ranged from 79 to 82F. It has an add-on Ice Cap variable rate fan that kicks up its speed when the air over the tank warms up. Seems to work since the room temp has been hovering around 80F recently.

It works with our portable. One way to check is to test your air conditioner with a basic timer (you porbably have one for your aquarium). If you can get it to go on and off using a timer, you can probably use the plug-in thermostat.

HTH

It's true...Tony's basement makes me sweat!

I will try this evening, great solution if it works.

I float large RO/Di Ice cubes that also act as top off. One cube can bring temp down 2-3 degrees C.

OMG are you other Calgary people in the same Calgary I am in. I have been roasting all summer long!

Tank is running with a chiller, and I am running with ice and cold beverages.