But if it was the the test kit wouldn't it be off when you tested the to water? Or by being bad does it mean they just give off bad readings when nitrates are present? Also I don't think it's the clams as even if they died in a 100 gallon would it even show a spike? Also do you have any nitrate removal going on like dsb or macro? I just thinned my macro out or I would offer you some of mine.