My RODI system came with a small JG bulkhead fitting so all I needed to do was drill a small hole & mount the thing. You may be able to find these bulkheads locally, I know they have them at Andrew Sheret here in BC, but don't think there are any Andrew Sheret businesses in Alberta. Search online for John Guest bulkhead & you should get plenty of hits.
Here's one link to get you started.
http://www.marinedepot.com/JG_1_4_in...FIROJG-vi.html