Major Die-offs

Our major die-off continues, primarily in the lab tank.  We have been removing about 10 fry per day - not good.  We have changed water numerous times, checked multiple parameters, and have done lots of cleanings.  The dead fish seem to be getting "moldy" very quickly after death.  We have recently added salt to the tank in hopes of destroying any fungal buildup.  The next thing will be to transfer all fish to the room tank and do a complete cleaning and start-over in the lab tank.  Not good!