So prior to my last water change on Sunday the water parameters in my tanks were all pretty good ammonia 0 nitrites 0, nitrates between 5 and 20. On Monday I tested again and all 12 tanks are showing a nitrite spike of ~2ppm. I tested the tap water and got 5ppm!!! Today ( Wednesday) its down to 1ppm but now long can the fish take these high doses of nitrites? No one is showing any apparent signs of stress at the moment, but if I don't want to drink it they shouldn't be living in it. Called the city water dept and MWRA but no one's bothered to return the call . Anyone have a brilliant idea on how to speed up the nitrite decomposition? To make matters worse I'm expecting some GBRs and CPDs tomorrow and I'm now afraid to put them in their tanks. Thanks for any suggestions Also, anyone have a recommendation for a ro di unit? After this I'm giving up on tap water!