Just went thru this last summer. None of the hardware/rona/Revys etc sell them anymore due to liability and most places I talked to were hesitate to sell me a pair even though I used to install them. I think I ended up going thru Calgary Overhead door? They are next to the Calgary Fastners on 42ave? SE, just up the hill from Standens springs.
They will need an old spring to match it up. The color codes don't mean anything anymore. Pull off an old one and bring it with it. If you cann't get it off then call a door guy cause you'll hurt yourself winding the new one.