balasts and fixtures?

[sir_dudeguy]

whats the difference between a balast and a fixture? are they the same? and do the light bulbs plug into a balast? i'm lost on how that all works.
i'm just asking because i'd like to get some lights that are about 175-200 watts for my 55 to grow some green star polyps or some other stuff like them, but i dont know what to look for as far as lighting, and i'm on a really limited amount of $.
thanks in advance
mike

[Jchillin]

The ballast controls the amount of power going to the bulbs. Think of it as a huge resistor (if the electricians will indulge that comparison). The fixture is the housing that holds all the equipment together.

Sorry but I have no suggestions for inexpensive lighting of that size other than checking ebay.

[noncentric]

Hi sir_

I've started doing some research on those types of things too, as my aquariums need some serious lighting modifications.

So far, it seems like parts progress like this:
(1) plug that goes into wall outlet is connected to the ballast by some length of cord
(2) ballast is connected to the bulb socket by some other length of cord
-- this is assuming a "remote" ballast, as opposed to "non-remote" ballasts that are right next to the bulb assembly.
-- also, ballasts can either be magnetic or electronic (I think electronic is more efficient, but not sure)
(3) bulb socket is what the bulb is inserted into
-- the wattage of the bulb has to be compatible with the power provided by the ballast
(4) all of these items are collectively considered a "fixture"

I hope my explanation didn't seem too simplified, it's just that I find it easier to understand things when I start from the beginning parts (plug) to the final parts (bulb) - so that is how I explained it.
I'm confident that if I misspoke or omitted anything, then others will provide the appropriate info.

As far as prices...I'm not sure of anywhere to get that much wattage for less than $150.

Good luck!