Lighting mounting/hanging

[Modemagic]

Is there a rule of thumb for hanging/mounting lights above a tank? I have (4) 65w PC bulbs for my tank and not really sure how high or low I should put them in relation to the tank. I do not run a canopy, so I can mount them as high or low as I need to go.

I would guess lower would be better and bring more light into the tank, but don't want to bake my glass tops either.

 

[Modemagic]

One thing I just noticed on my bulbs... two of them light up blue in color, and two of them are white. Should I be running these at the same time? Different times? Whats the purpose of the different colors?

<---- still pretty 'lighting retarded'

 

[Covey]

PCs can sit directily on the top of the aquarium. They need to be as close as possible.

Some people run both at the same time alot of people will turn on the blue bulbs first then the daylights. Then at night switch the daylights off first then the blue bulbs to give sort of a sunrise sunset effect.

Its person a choice.