flourescent bulb question

[buckeye88]

I want to set up a 10 gallon tank for my girlfriend with a lighting fixture that has 2 18" 15 watt flourescent bulbs (30 watts total). I would like to put some soft corals like leathers and mushrooms in there that don't require as high lighting. I went to petsmart to look at their bulbs and there were different kinds of 18" 15 watt and something like 18,000 K bulbs but all recommended for different things.
The lights that were recommended for corals were the same size, wattage and "K" (whatever that means) as the ones that were not for corals but were conciderably more expensive. What makes these ideal for corals?
If there's no differance than I'll but the cheap ones but if they really will promote coral growth that I'll gladly pay the extra money. Thanks for the help

!

 

[scsinet]

Anything in the range of 10,000K to 20,000K will be suitable for corals, within that range, the lower (towards 10K) are going to be better for corals, but within that range, it's more a matter of how it looks to your eyes than anything else. The higher the kelvin (K) rating, the bluer the light is going to look.

 

[buckeye88]

ahh, so do you feel that it is worth it to buy the more expensive bulbs or do they just put "suitable for corals" on the package to try to get suckers like me to buy them?

 

[scsinet]

It's the kelvin range more than anything else. I'd say the "coral" label is just a gimmick.

 

[buckeye88]

ok, I thought so! Thanks alot

 

[michaeltx]

yep look at the K rating but if it was me I would look into a PC setup for the tank instead of Normal flourescent bulbs it will make the tank look and grow much better and with a 10 gallon tank it wont be to expensive either.
mike