UV Lighting (and the rest of the big names) only makes their bulbs down to 22" (
AFAIK). If your bulbs are smaller than that (they really measure under 17"? And 18 or 20 watts?) I think you will find your choices in color quite limited. (Not that it's the end of the world....or even a bad thing.)
Positive things to consider:
- Almost all bulbs produced for and sold in the hobby today will make your corals happy and keep them growing for 6 months, maybe more. Even the cheapies.
- Getting the intensity is the key, and 6 x T5HO is a proven solution.
- After the first two concerns, "getting the right colors" is both unimportant and subjective to you. In other words, the colors are for you, not the animals in the tank. While (e.g.) 250w Radium 20,000K's on magnetic/HQI ballasts might be considered an ideal color of reef lighting, if you like what you see in your tank currently - success! Change if you want to experiment, but if not then certainly don't feel obligated by anything you read online.
Current USA's offering for 18" bulbs seems to be about the best going - they offer a purple (called a "grow light" back in the day) as well as the basic daylight, 10K and blue. About $14/ea from what I see.
($14*6=$84 per refill twice a year + $35/yr in power. $203/yr to operate that T5 system.)
I would like to point out that others have gutted T5 and halide hoods like yours and wired in GU10 LED bulbs. For about the price of one set of replacement T5's you could do the same.
When you convert to LED, power usage drops to laughably low levels (for me: 360 watts of Radium halide down to ~60-100 watts of GU10 LED), heat issues disappear completely and bulbs "almost never" have to be replaced. Check out my Reef2Reef blog (click my name) for some related reading and links - let me know if you have any questions!
($5*10 bulbs=$50 per complete set + $11/yr in power. $11/yr to operate a GU10 system.)
While I like GU10 bulbs due to cost, flexibility and simplicity of installation, I have to point out (and I'm sure you may know) that there are also a million and one great DIY LED solutions posted here on R2R and around the web and several great commercial LED solutions on the market. All are good and economically sensible vs T5 or halide lighting - really worth considering.
Good luck!
-Matt
