Right lights for a 40g reef tank

I'm going to be taking a 40g acrylic tank off a friend of mine and turning it into a small reef tank. I'm stuck on trying to pick the best type of lighting for the situation. The tank is ~36"w so I was planning on using 36" PC lights.

I was planning on keeping nearly half a dozen smaller fish, plenty of live rock, a few corals eventually (but probably not many and probably not from the start), and a few inverts.

I was toying with getting a single tube 36" 92 watt PC Coralife light, but I'm concerned that may not be enough light. I know the fish aren't too critical on lighting and the same goes with the shrimps and snails, etc., but my main concern is the amount of light available for the live rock and corals (when I eventually add them).

Thanks!

You're right. I probably should mention the types of corals, but I'm not completely sure yet. I know something I may consider is something like a small bubble coral and things similar to that. Clams are out.

I agree that lighting should be taken very seriously, but after talking to my friend again last night, we agreed that especially as a beginner and this being my first SW tank, I probably shouldn't and don't need to go overboard on lighting. I realize that the type of lighting I choose will directly affect the type of life I can put in the tank as far as corals are concerned, but at the same time I will likely start extrememely slow on corals and try to choose ones that will do okay in the light I pick.

I don't have the tank on hand yet, but I believe the tank is about 16" deep w/o sand. So, after sand, I'd say it'll probably be about 13" or so deep.

Can you tell me why the dual over the single?

I think metal halides are out in this case. This being my first SW tank and considering the types of fish, corals and inverts I plan to keep will not require quite that much power I think it'd only be overkill in this case.

I'm really leaning towards the single 92w strip. If I did go higher I'd probably go with the 175w dual strip, but I doubt I'd do that.

Plus considering the depth of the tank, the higher wattages may just be too much light and inhibit growth of some of the coraline algi.

Can anybody confirm or deny my last statement?

If my calculations are anywhere near correct... I figure by the time I add sand and rock I'll have anywhere between 25-27 gallons of water in the tank. Now, with the 92w light, I'd be getting approx. 3 - 3.5 watts per gallon. With a 175w light I'd be getting around 6.5 - 7 watts per gallon. Seems like the latter might be a little high, but I'm new so that's why I'm asking

Secondly, I'm wondering if maybe instead of inhibiting coraline algi growth with the higher wattage light... would by chance it just inhibit certain kinds of coraline algi, but promote different types instead?