Chris,

This is not from the perspective of bulb life or anything else. You may very well be sitting in front of your tank for that many hours. That's why you want your tank lite for so long. Most of us are not. I once came across an article that helped me with my lighting though. The wonderful thing about timers and tanks in our homes is we can "set" when we want the sun to rise and fall. If your an early riser and spend most of your morning in front of your tank then you can set your timers to reflect this. If you like to stare at your tank at night then set the timers to stay on longer for when you get home.

There is nothing that says you have to stay with a noon time rise and fall. As long as the tank isn't in a room that will be naturally lite by the sun then you can determine the lighting cycle. Therefore you don't have to have an unnaturally long lighting cycle of 13-14 hours. You can even bump the weekend hours up to match your schedule as long as your not throwing it off by too much. The sun never rises and falls at the same time naturally.

This is just something to consider. I also have MH lights. I had to add additional lights so that I could accomplish what I wanted. My MH are on for 6 hours a day. The PC lights fill in the gaps and the actinics come on in the morning and fade out the day. My lights are on for a total of 12 hours. Actinics make up an hour 1/2 of that alone. PC's are on the other 5.

I don't know if this helps you at all. Just what I ended up doing for my tank.

Angie