We have a RES that's approximately 3 years old, about 6 inches long in a 20 gal.tank, 3/4 full of constantly filter water (150 gal/hr)[I do a complete water change every month the filtering elemnts are changed] with a sunning perch and lamp. He eats well, is very active and both shells are hard. HOWEVER, the lines between the upper plates have become very clearly delineated, almost appearing to be cracks and is shell is coverd with a hard white film (due to hard water?. He has always been cantankerous, a real "toughie" and that's one of the qualities that endears him to us. Do these conditions represent any health condition that we should be concerned about?
thanks in advance.
