Here is something interesting but also something that I suspected.
Chilliwack gets its water from an aquifer (ground water). It is much more susceptible to contamination (from what I have heard.. I am not an expert).
Have you checked your source for nitrate or phosphates? (right out of the tap)
You can find more info RE: your water here:
http://www.gov.chilliwack.bc.ca/main/page.cfm?id=1249
I forgot to say.. I have a Lawnmower Blenny that keeps my green algaes in check.