Sorry to be confusing...
To clear up two issues- photoperiod length and LED
First I was suggesting that if you're really only going to be home at night, than simply have the photoperiod during that time. If you go to bed at ten every night and you want an 8 hour photoperiod than turn the lights on at 2pm and have them run until 10 when you're going to sleep. That way you get to see the fish and they get a good length of sunlight!
Secondly, there are many very different types of leds. Some may not contribute to photosynthesis, however I could certainly set up an led system that was more powerful and more usable than any t5 system over the same surface area. I was just under the impression that you wanted to add an LED fixture like that as well as your t5s and I was stating that that would be too much light.
Aha! Gotcha now. Well, I would most likely be jerry rigging a strip light onto the T5 fixture. The room where my tank is gets a bit of natural sunlight, so I think the photoperiod would have to be the same as natural sunlight around here. Otherwise, I wouldn't be able to totally control everything I think. You can tell me if Im wrong as I'd like to know for sure. It would be using regular everyday LED's, nothing super powered. I Might even stick a Marineland LED fixture on there as I believe I would have enough room due to my current T5 fixture only being 5.5" wide.
I think when the T5 photo period ended, I would turn on regular LED's for the remainder of my viewing time. Fish would have blackout for atleast 7 hours like I would have atleast 7 hours of sleep. I may be getting WAY too technical here, but I would like to eliminate as many mistakes as possible before planting the crap out of this tank, and suscepting any livestock to stress or unfavorable conditions.
If this method would be too uncontrollable CO2/photosynth-wise, I guess I could always shade my room instead and just stick with the T5. That wold also save me a bit of money LOL.
However, the sunrise sunset option would be pretty sweet so I will have to implement that and video it for you guys!