The same company listed in a previous reply also has a retrofit kit called a NANO light set in the clearance section due to over stock of the item for $24.00 and it will handle 28 to 65 watt PC bulbs.........I wold retro one of those with the PC lights into my setup instead of going for a T5 bulb driven by a ballast that will not power it up sufficiently.........I have a 16 gal bowfront AGA, and managed to squeeze a total of 168.5 watts of PC lighting over it, without going over the original dimensions of the top of the tank.......its foot print is roughly that of a 10 gal tank in regards to width and length. I have 1 coralife 96watt quad, 2, 28 watt PC, 1 13 watt PC and 2, 3/4 watt lunar lights. Needless to say that tank is well lit. I have it all under a custom made acrylic hood. The $24.00 for those nano ballasts complete with bulb clips are well worth that price, so all you really need is a space to fit a 28 watt PC bulb, which requires approximately 14" x 3" including reflector.......So if yur usuing a standard typical aquarium hood, it would be a simple matter to gut it out of original electrical items, and mount the bulb socket and clips on original reflector and hood..........or you could easily use the same ballast and go with a higher wattage bulb and still fit inside that hood, but I would add a small muffin fan on one end for some cooling, but you would be way above average lghting on most small tanks withjout spending much money. IIRC that sight that has these lights goes by Helios as well as "hello" lights. If you want the website addy email me.
