Burfy,
From what I can remember quartz halogen lights do not produce anywhere near the same amount of lumens per watt (approx 17) as flourescent lights will (in most cases approx 70 lumens per watt), therefore you need to supply a lot more watts of halogen to establish the same amount of light obtained with a flourescent.
So although you could use them the light source would be a lot weaker & the colour given off is not too attractive either (yellow hue), which would affect both plant / fish growth and health.
On top of this halogen lights also generate a greater heat source so if you are already in a warm climate tank temp could be a consideration.
My recommendation would be to go flourescent and either:
1) Get a new hood built.
2) See if you DIY your hood to take flourescent tubes.
3) DIY a new hood with flourescent
I am not at all DIY minded but I am sure if you asked around some-one would be able to help you out with the actual working / parts required etc of it.......
Like I said a lot of this is from memeory so it may be an idea to wait for some-one else brave to chip in.......
HTH some.....
