How about going to Wal-Mart or a similar store and getting a $12 timer? It would reduce the stress on you. Get one with a battery back up...kind of like you alarm clock. I shoot for 8 hours, others like 10, other than that, is too much. Think of your tank as an extension of the ocean. In any particular region, there is generally not a 12 hour light cycle....I know, Alaska and propbably anything around that longitude does, at some point in the year, but that is cold water stuff! LOL!