Newbie lighting question

[ebius]

Hello all. I have been looking around for quite some time and have found the answers to most of my questions. Just a quick thanks to everyone for the great advice you have!! I have done several searches and cannot find what i now need to know.

I am new to saltwater and am going tostart a reef. I have had a rather large tank fall into my lap(119 Gal, 48x18x31) This tank looks a little deep tho at 31". Will i have to push much more light to get to the bottom? I am looking at MH. Also, when i am looking at lighting it doesn't seem like i can get 7 wpg in a 110 Gal that is only 48" wide. Do you take the total watts or the lighting fixture, or just the MH lights in it? Most of the 48" hoods i have found only have 2x150 MH lights but also have 2x150ish Dual Actinic. Would this be a 300 watt hood, or 600? Also, can I just replace the 150 watt MH bulbs with like 2 250 bulbs?

I know lighting can be a real brain teaser, but I am really trying to figure all this out before i get the tank up and going. Idealy I would have enough light to keep anything I find that I like. TIA for any advice you guys have.

 

[electrikat]

The ballast wattage has to match the bulb wattage, but total wattage is all lights combined blue and regular. You could get a hood with 2 400 watt bulbs or you could go with 2 250w plus some pc lighting in the blues to bring up your wattage.

 

[ebius]

Thanks for the info. I guess one thing that im still a little worried about is getting light to the bottom of the tank. Is there a rule of thumb when thinking about this? Will a 150 watt MH reach the bottom of a 31" tank? I only plan on buying one hood, so I want to make sure that I get the right one. The biggest problem that I have is the only lights i see that are bigger than 150-175 are retro fit. I would really like to have one hood that sits on legs. If anyone has any suggestions I would love to hear them, and a link would be even better! Thanks again.

 

[electrikat]

I don't know the rule of thumb(if any)for depth lighting. I'm sure one of the advisors will though.

 

[Salttanker]

At 31" deep, I would be inclined to go for 2 400W MH. You have to figure in the distance from the canopy to the water if it is tall, in which mine is about 12" off the water. I would use retro lighting if you can't find a kit all inclusive with 400w.

Mike