Hi, I am of the belief, you get what you pay for, and lighting is not something you want to skimp on.GHL Mitra LX with 6 identical smaller pucks means the led color ratio are not very flexible. You end up with too many reds and greens and not enough blues, violets, and UVs. For high PUR, it's not ideal. Plus with such bulky design, you're physical limited on how many you can add and arrange over a tank. Price wise, you can not beat 8 ReeFi Duo Extremes for $5200, much lower than $9000 estimate.
Hi, I used M/H lights for many decades on all my systems including my current 600 gallon system. Even with the best reflectors you would need 8 of them, the same amount of the Mitra LX7206 lights I use now, and since I live in South Florida, the amount of heat in the fish room has been greatly reduced, thus I have a lot lower electric bill, due to the savings on the A/C not running nearly as much in the fish room. There is a decrease in the electric bill, switching from M/H to the Mitra’s, but the difference would take a very long time to see a savings. With the bulb replacement and the electrical savings, you should start seeing a savings in about 5 or so years. I went with LEDS this time around due to the ease of use, and the ease of changing the color spectrum, without changing the bulbs.OP, I think your initial selection of 4 x 250 wt MH with either a row of T5 or LED (for dawn/ dusk ) supplement would be a great choice. I've lit a 4ft long tank with a single 250 MH bulb before, so I don't think the 4 ft width is an issue for your tank. Really just a matter of reflector &/or bulb height to get the coverage you need. You have to factor in that multiple bulbs can really bump the light coverage on a larger tank ,as you'll get overlap from the other bulbs & reflectors. Cross braces will also dictate to a degree how many bulbs you might need. Sounds like an awesome build & best of luck.