there is a girl i know who kept losing all kinds of her fish,and tested the water for nitrates,amonia,nitrites,ect.and every thing seemed to be fine,untill she decided to finaly check her saline level and it pegged the needle to the top of the saline tester.so she more the less pickled her fish,and by adding fresh water she reversed her problem,and whats left of her fish are fine,i'm assuming?!