Recently I've been supplying light to my smaller vivaria using 13 watt compact fluorescent fixtures assembled from raw parts. There has been a lot of interest in these fixtures so following are the sources and part numbers used to assemble these units. I am not an electrician so use these instructions at your own risk.
Update: I have also built 9w units to power the new 9 watt Compact Night bulbs.
McMaster-Carr part #'s are:
ballast
8305K21 - $4.65
G23 lamp holder 8310K13 - $2.28
Everything else is same as below.
Parts:
(1) Advance magnetic ballast
(1) GX23 lamp holder
(1) 13w CF bulb (5000°K)
(1) Grounded power cord (salvaged computer power cords work well)
(2) Wire nuts - available at any hardware store
18 gauge hook-up wire
I purchase the lamp holders, ballast, and wire from McMaster-Carr
Part numbers are:
ballast - part # 8305K24 - $5.10
lamp holder - part # 8310K23 - $2.28 (this is for horizontal holders, vertical holders are also available)
18g hook-up wire - part# 8073K64 - $8.79 per 100 ft. (also available locally)
The bulbs are Phillips PL-S 13W/50 twin tube bulbs. I get them from Bulbs.com. There is a $15 minimum order.
Part number: PL-S 13W/50
New! David Doyle pointed me to a light that appears to produce UV and 5000K. Price is $7.26. I have not tried this light but it looks interesting. If you haven't visited, you should check out David's Lighting Links page for a plethora of information about lighting vivaria and aquaria.
Wiring:
Wiring
these units is a 5 minute operation. Below is the wiring diagram for a
single unit. Of course you can wire multiple ballasts to a single power
cord. The ground is attached to the metal frame of the ballast and can be
attached with one of the mounting screws. To ground multiple ballast you
either need to run jumper wires between the ballasts or mount the ballasts to a
common metallic surface that is grounded.
Reflectors:
Many people have asked about using reflectors with these lights. There are some excellent kits available from Aquarium Hobby Supply that are essentially the same as these lights in kit form with a very nice reflector. Of course they cost more and it is up to you to decide if the claimed 60% increase in light output is worth the cost. It's useful to note that these reflectors are designed for the aquarium hobby and direct light downward at a steep angle so it penetrates water. This is a great design but not really necessary for a vivarium. Light bouncing around at shallow angles in a vivarium still gets intercepted by plants instead of being reflected and lost as it is in an aquarium situation. Because of this, vivarium reflectors can probably achieve good efficiency without using advanced designs. I very recently started lining my hoods with standard galvanized sheet metal used to pan HVAC ducting. This is available at any hardware store for a few dollars per sheet. This provides a reasonably reflective surface that yields a noticeable improvement in light output. It also provides a common ground for multiple ballasts.
My Recommendations:
These lights are great for special situations where you want allot of light but have limited space for bulbs. However, I do not recommend them for general lighting. My personal recommendation is to use the largest CF bulbs you can for a given setup and reduce the number of bulbs. Many small CF bulbs produce more heat than a single larger bulb of comparable total wattage. Additionally, these bulbs use electro-magnetic ballasts that produce additional heat and hum. I currently use the Aquarium Hobby Supply Bright Light Kits on all vivaria except those few that don't have enough room in the hood to fit the larger bulbs. Honestly, these kits are hard to beat and use high quality electronic ballasts that are more efficient, produce more light, no heat, and no hum. One modification I make to the AH kits is to flatten the reflector significantly before installing. This provides a more even spread of light in the vivarium but will reduce the intensity of light penetrating water areas so you might want to forego this modification in a paludarium.
Caution:
These lights put out a lot of light but they get much hotter than conventional fluorescent bulbs. Make sure you design your light fixtures so they are safe for you, your animals, and your home.