I recently put two 15W, 18", 18000K Aqua-Glo bulbs over my 55, and while the spectrum is great and makes everything look beautiful they seemed a little dim. So I added a socket for a secondary 10W aquarium compact fluorescent in each hood. It was a simple mod. I had to cut away some of the inner plastic bulb housing to make room for the bulbs, and then just added $1.59 sockets from Home Depot to each one. I can squeeze two of the CF bulbs in there if I cut a bit more material out and move the transformer from where it's currently attached. I also added LED moon lights (horray for $0.75 leftover Christmas lights!).
This looks cool, very creative!! I will check my light hood and see if I can do something similar. I wish they had a 25W or 30W light that I could just use to replace the current one. Your idea seems good. Thanks!!