Marine Lighting / Algae questions

[d...@ho.qsun.att.com]

I have several questions regarding a 75 gallon FISH ONLY marine Aquarium:

For fish only, how important is lighting, as far as the fish are concerned ?
I have one fluorescent bulb, the tank gets indirect sunlight.

Quarts Halogen lights are cheap (300 watts for $9.00). Other than the fact that
they generate more heat than light, any problems with these ? I plan to turn
these on only when I am watching my fish.

I have white coral, and crushed coral, and a black background. I want to keep
that bright white look and do not want algae to get all over the coral. Is this
wise ?

Does algae get rid of nitrates ?

Is the algae important to feed the fish ?

Two of my freshwater tanks have algae, a third with a UV Steralizer does not.
Does the UV keep the algae away ? Can I use UV to keep algae out of the tank ?

One of the freshwater tanks has brown algae, the other has green. Why ? Are
these good or bad ? Which is better ?

I am getting brown spots (looks like rust) on some of my coral is this algae ?
How can I get rid of it ?

A friend suggested that I use lights over my sump and grow algae there as part
of the biological filtering. Does this make sense ? If so, is there any way to
have algae in the sump but not in the tank ?

Thanks in advance,

Dan