From what I've read it's actually recommended you add variations between 1 teaspoon to 1 tablespoon of aquarium salt per 5 gallons of water. This will prevent diseases and also help with the general well being.
Info taken from bettatalk.com, amongst others.
If the salinity drops from 1.007 to 1.004 or so, would that still be too much of a sudden change?
Thanks! You have been the most helpful so far. I think osmotic shock is the problem I'm facing.
Refractometers. I don't want to buy cheap inaccurate knock-offs. Is this ok?
http://cgi.ebay.com/Salinity-Salt-Re...QQcmdZViewItem