Mark,
Surprised that you don't get any ammonia readings from testing the tapwater. What kit are you using? I get about 1 ppp ammonia using an Aquarium Pharmaceuticals kit. When I add Prime to tapwater, I get 0 ppm ammonia.
BTW, ammonia is definitely added to Edmonton's water. It is added to chlorine to make the disinfecting properties of chlorine longer lasting and more effective. The chlorine/ammonia compound is called chloramine. Chloramine has been in Edmonton's drinking water for quite awhile, longer than I have been reefkeeping since 1999.
Epcor's E.L. Smith Water Treatment Process, where it shows where in the water treatment process chlorine and ammonia are added ....
http://www.epcor.ca/Communities/Albe...eWTProcess.htm
2005 Monthly Water Quality Summary Reports, pick a month and look for
Total Residual Chlorine. This is how Epcor reports chloramine, which isn't very useful to us as aquarists, but what are you gonna do....
http://www.epcor.ca/Customers/Commer...ry+Reports.htm
Epcor's Water Quality Glossary of Terms....
http://www.epcor.ca/Customers/Commer...tyGlossary.htm
Have just been on the phone with a guy from Epcor. He said chloramine, chlorine and ammonia are not listed as such, but to look for
Chlorine, (Total Residual) in the
Glossary of Terms page (above).