Newbie Mh help

[Mabus]

I am purchasing MH's for the first time. I have a few questions about some lights I've picked. Could you guys please answer a few questions for me?

Ballast: MH ballasts 2x: 250W Advance (M58)
Bulbs: MH Bulb 2x: 250W 20,000K XM
1 3 inch fan

1. Will 20k bulbs look good and provide the right light to allow giant clams and sps to thrive?

2. Would 175 watt 10k's and VHO supplementation work better?

3. Will one 3.5 inch fan be enought to manage the heat of these lights?

4. If I buy a ballast rated for 400W, will there be any problems running a 250 watt bulb?

[TJcop]

1. Looks are up to the viewer. You will have enough light for clams/sps, although 10K usually gives faster growth.
2. No....but I guess it depends on the PAR value. Does a 175w 10K bulb have a higher PAR than a 250w 20K bulb?
3. Depends.
How big is your tank and what are the dimensions? Answering that will help with your lighting question.

[nodle]

No you can't run a 250watt on a 400 watt ballast.
20k bulbs will give more of a blue look to your tank where as the 10k buld will look yellow next to the 20k or even the 14ks all depends on what you like.
I have one 4inch fan aimed at my 250watt light and you can't feel any heat on the reflector but your arm still gets hot under the bulb when feeding, Vaccing or being a pain in the @## to the fish by making that one last rock movement.
Dave

[Mabus]

I have a 55 gallon (48"x20"x13")

So, the 10kk's give increased growth vs. the 20kk's. How much difference in growth is there between the two?