my fresh water tank is infested with these creatures..this is the second infestation in the same tank does anyone know how to kill copapods. i have already broke this tank all the way down to hopefully get rid of these creatures and they lived through chlorine,gravel filtered and cleaned then i set the tank back up again and i noticed they were back again is there anything i can use to kill them off i was thinking maybe dumping alot of sea salt into the tank