Inconsistent System

Sometimes my ATO will work and sometimes not. I cannot figure out how to get it running again. I have a 65 gallon Rea Sea and the ATO has been in place about a month. When it works it great. It is simply inconsistent with replacing the water each day. It will work fine for several days and then stop keeping the tank topped off. How do the indicator lamps tell me tell me what . Obviously they are red and blue for power and pump. However, when resetting, what is the proper sequence?