ive had my two smooth soft shells for awhile now. but ive noticed both there shells are starting to almost roll up by there tails almost like its a wave. is this a problem and if so how do i fix it. there about 3 inches long in a 135 gallon tank with nothing else my tanks water is perfect im filtering about 650 to 700 gallons an hour. could my lighting be to strong. they eat great and love to bask and dig in the sand verry active please help.