I have an old AquaRite w/ a brand new T-3 cell. When I use the diagnostic button to set the cell type from the default T-15 to T-3 it only remembers it as long as the pump timer is on. As soon as the pump timer shuts off it forgets the T-3 and the next morning it will be back to T-15 again. Is there some sort of battery on the board? I could not find one.