I tried doing this with a fluval 103 about 4 years ago. It would work for a few days and then get an airlock since the pump head is at the top of the canister filter. I also had to adjust the drip rate on a daily basis. I eventually stopped using it.
My Geo reactor is much nicer looking and...
I own an original aquacontroller as well. Bought it back in '96 or '97. I would suggest you pay extra to get a backlit unit. Backlighting was not an option when I bought mine. That's about the only thing I wished mine had.
You can pick up extra control modules from any Radioshack. They are...