Ok after reading all the posts I decided i had nothing to lose. One of my squamosas was obviously unhappy and not getting any better. About half of the mantle was crimped so I did a 30 min fresh water dip. Turned the lights out and checked on him this morning after the lights had been on for a few hours. Definite change. Not sure if for the better but definite response. The clam was fully open looking like gaping but mantle extended. i will check again today after the lights come on. will post results.