Wow that’s terrible. So sorry to hear, but thank you for the warning to the rest of us. Maybe you’ll save someone else’s fish!It's nice to have/use large containers however if/when the doser goes out of whack it can dose the total amount of liquid in the container. This happened to me with a Pacific Sun Kore 5 doser. It dumped 800ml of trace elements into my display tank in 2 hours. The proper dosage was 16ml per day. This killed all my tangs at the time...7 tangs to be exact. Needless to say I never put too much liquid in a container that can have such an effect in the event things go bad.