Just throwing this out there, maybe it can help others. I did a big (50%) water change yesterday and immediately lost fish afterwards. I did not test the water out of the tap first. After updating my test kit for missing reagents I learned that the pH had crashed and ammonia was high. Next I tested the tap water and to my surprise it was ~5.5 pH and ~1.4 ppm ammonia! I'm in central Abbotsford, and can't be sure if it's widespread or just my building complex. If anyone has a good understanding of how condo water/plumbing systems work I'd like to get a better understanding.