OK right in the middle of huge issue but I will try to respond later -sounds like your nitrites would be the issue - can you give a full break down of tank (what you have livestock, equipment, inverts/lighting and photoperiod/what kind of water do you use for WC's/substrate CC or DSB - filtation - any recent additions .....how often you feed)?? Also - I would prepare a water change of some size (like 20-40%) now and execute it once your newly mixed water is ready.....
lastly do a search for high nitrites and you will find some other helpful info ....
OK everyone else returning from "smoke" break need to get back to this pesky work thing ....