Tall plant tank lighting... metal halide?

I should be picking up a tank tomorrow, a used 150XH tank (31" tall). I plan on this replacing my 75G as my CO2 plant tank. I am going to take my time setting it up, have to build a stand and all yet, probably wont be operating until early next year so I have time to do the research and look for good deals, basically want to do everything correct right from the start.

So one of my first difficulties will be in addressing the lighting, which on a 31" tall tank will have to be intense. I figure I have 2 main options, PC and MH. So far my research has shown that both will work well but seems MH might have the edge on intensity for such a deep tank. And the cost is fairly close between the two for what I can tell.

To address MH first. There seems to be 2 types; HQI and the bulb-shaped kind. I have heard good things about the HQI but havent seen many in the 5000-7000K rangeand 175W so (150W is common but I dont beleive enough for 31"). I know I will probably want an electronic ballast too for effeciency.

Or there is PC lights, like the ever popular ahsupply. I was thinking about either the 4x96W or 6x96W w/ bulbs 5000-6700K. The 6x96 is pushing my budget limits at about $540 with bulbs and shipping, and gives 3.84wpg (many say PC are 150% effecient for the wpg rule so that would actually then be 5.76wpg if you take this extra effeciency into account). The 4x96W kit would be a more managable $350 but only 2.56wpg or 3.84wpg(assuming 150%) which is a bit low considering the depth IMHO.

I could swing the more expensive kit but, ouch...

For the price of the more expensive kit I could probably get 2 MH pendants. Also bulb replacement for the PC would be about $200 (for 6x98) yikes!!! MH is still fairly pricey but 2x175's would be about $100-$130.

Gee whiz lighting is expensive... on my 75 I use ODNO T8/T6 lighting which is pretty cheap. But I just dont think that would work on the 150XH.

Ok, those T5 fixtures are in the running. I had sort of dismissed t5's earlier since I just didnt see alot of selection. But I like the sounds of the 9-bend reflector. Price is comparable with some of the others I am looking at. How is your bulb life?

Well, heat might actually be usefull in my situation... depends were the tank is going. I am considering the possibility it might be too heavy for were my 75 is. If I put it downstairs (family room) it will be on a concrete floor, but the room is usually much cooler than the rest of the house (mid 60's typically). I will insulate the base and the back, and probably get larger than otherwise heaters. During the lighting period the extra heat would probably just mean the heaters wouldnt run as much or at all.

Ok, assuming just for a second I go for metal halide... does anyone have any opinions on wether or not 2 x 150W HQI bulbs would be enough? HQI's seem to only be available in 150W or 250W versions. I dont know if 2 x 250W would be too much. If I go for 2 bulbs they will probably both be 5,000-7,000K rated. Or I could get 2 x 175W or 2 x 200W screw in type. I wouldnt mind doing a third at 10,000K but I'd have to stick with the 150's so my wattage doesnt get too high, but the price takes a big jump having to get 3.

I'll most likely have one or two t8's in there as well so I can turn them on first in the morning and last at night for less instantanious blast of light. I also wouldnt mind building a DIY MH setup, but not sure if I would save much money or not, and I have seen alot of the fixtures say they include a UV blocking lens - not sure if thats something I could get seperate or not (or not sure if its needed?).

P.S. I just picked the tank up this afternoon. Wasnt in as nice a shape as the prev owner lead me to beleive, but still decent. My first used tank purchase - not sure if will do it again or atleast no deal until I get to see it.

Gatorguy - thats good to know you have had good luck with just the 4x55W kit on your tall tank. Out of curiosity, do you have many high light plants? I actually just got a response back from Kim at ahsupply (asked thier opinion on lighting a tall tank) and was recomended that the 4 x 96W kit would be plenty even for most light-demanding plants in a 31" tall tank... and can always add another later if I find otherwise. That is good news to me as thats a total of under $350 for the kit, bulbs, and shipping.

Still pricing out diy MH options, and still considering the TEK light T5 (trying to find cheaper source). Thanks for all the great info everyone!

reiverix - what kind of bulbs do you use for your planted tank with that t5 fixture?