I've used salt only when treating for ich, and I can't truly say if it helped or not, but personally I think there was a bit of a difference. It is supposed to help fight some disease, and to assist with breathing when they are stressed, etc. I really wish I knew if it was all propoganda or not, does anyone TRULY know the benefits if any of salt? the man at my lfs says he keeps it in his tank all the time, but I just couldn't do that, after my ich treatments i do like a 60% water change and than a 50% a few days after just to help remove it all from my system.