i replaced the heating element. the water warmed up to 97. it stayed there for a week, and now it has cooled off to 84. it's a 5500 kw 240 volt element. last night when i turned the temp down (it has a turn nob) i saw a blue flash when the themostat clicked off. what could be wrong, do i need to replace the temostat ( one or both)? there is a long one and a short one.