I bought my flex PVC type hose from new line (
http://new-line.com). They have 2 offices locally, one in Burnaby and another one in Langley. I am sure they do mail order too.
I used something called spa flex. I think that's the stuff that most people use when they need flexible tubing for their aquarium. Look under their water suction hose catalog. It has both tigerflex and spa flex listed there.