another suggestion on the flood light- I recommend just getting a dome lamp, they are similar to the one you have, but are larger. and just use a compact florescent curly bulb and set it on top of the glass. The clip on the glass baffle will get rusty, and is an electrical hazard. Plus, getting rid of the flood light will save you money and wont pump tons of heat into the system. I have used CF bulbs and dome lamps over fuges for many years with no ill effects. In my experience, the closer the bulb is to 10,000K (i think the highest in normal cf bulbs is 9,200K), the more good algae grows, with less of a chance of diatoms, cyano, GHA, etc.
For baffles to the return pump, I have always used old vhs tapes to space the glass, and have found that method to be great