Story: I have lived in a dorm since last August with my fish tank. Everything was fine and dandy until we had a scheduled power outage. Now there is ammonia in our tap water .50ppm. Could my tank be going through a mini cycle due to lack of oxygen in the filters during those 7hours? Parameters since water change this afternoon 7.6 pH 0.25ppm Ammonia 0.0 ppm Nitrite 0.5ppm Nitrate I will retest tomorrow between classes Should I just take the expense and get bottled "spring" water to change my water?? 20 gallon long running since January 2016 10 gold Barbs 1 BN 1 Female Betta (gets along fine with everyone) A herd of MTS I do water changes twice a week between 25-50% (getting a python WC next week) I have two HOB filters that turn 325gph of water I am lightly planted (expecting a shipment of plants Wednesday) I usually just use prime, but since the extra ammonia I have added stress coat & stress zyme after this water change when I realized my tap was the issue.