Lights on for how long ?

[DiverDude]

Noob question here....

I have a 28 Gal setup I just got. Tank was established and I've moved it to my place. Everything seems fine and water is nice and clear. No fish yet; just LR a few snails and a hermit crab.

I have a horrible work schedule and I'm out of the house from ~8 am to 8 or 9pm. When I get up, I of course turn the LED moonlights off and turn the main lights on (50/50 PC light) and gaze upon my little slice of ocean. I then leave them on until I go to bed around 11pm. Was thinking about this last night and that's a LOT of daylight !!

I'm going to put it on a timer, I think, so that it limits it to about 10 hours or so (1pm - 11pm ?). This will mean I can't see it in the morning but....

How much light is too much ? Opinions ?

I'm considering building a canopy for this that will have 2x75W MH and some T5's. If I do this, would the INTENSITY of the light dictate a change in exposure time at all, or should I just be trying to mimic an average amount of 'day' ?

Thanks.