Well, I cant say what would be the best, I am still figuring out what I want to do for lighting on my next two tanks I am setting up. But if its cost of bulb replacement your concerned with ODNO T8's would be the way to go. 2x96W bulbs from ahsupply cost abotu the same as a 250W HQI. If your willing to run 6500K's you can replace T8's for like $3 a pop. maybe you could try your same setup but limiting you MH burn time, how many hours a day do you run it now? Is it vented enough? I am not familiar with your tank, is it a 4' tank or shorter? I was assuming 4' T8 bulbs, and if that is the case 4 bulbs 2X each should be plenty of light I would think.