Ace I saw your light setup... I'll save you some electricity... That design will not work because almost none of the light is getting to the screen; it's like the sun right before it sets on the horizon. You want the lights on the side of the screens, not the top, like the sun at noon. A single 23 bulb hanging in between your two screens will do more filtering than the three bulbs you have now. Get a new lid, and hang the bulbs down to the middle of the screens.
Clean one whole screen a week.
No fan needed for filtering.
Day or night does not matter for filtering.