I think you need to step back and start thinking from the start. You apparently can afford $1000 or more for lighting, but you are using the cheapest substrate material you could get. As a result of the substrate decision, you have a big tannins issue, making lighting the tank more difficult than it needs to be.
Why not switch to a commercial aquarium substrate, that doesn't release that much tannins, using some of the money you plan to spend on lights? You can buy a lot of ADA Aquasoil for that much money, and have a proven great substrate, that doesn't give you the tannin problem. Your tank is probably something like 96" x 30" x 30", which can easily be lighted with T5HO, or LEDs. You could use 4 of these 48" lights, http://www.catalinaaquarium.com/stor...oducts_id=1842
in two rows, separated by about a foot, and get about 50 micromols of PAR at the substrate, more than enough to grow any plants.
Then, start planning a CO2 system, which will be essential, and is by far the hardest thing to get right on a big tank like that.