i'm looking to upgrade to a rimless 40g breeder. i like the larger 36"x18" footprint better than my current 36"x12" 30g. i also want to upgrade my lights. i currently have 55w PC lighting. i think i want to get t5s instead of the 96w PCs. i'm looking to get enough lite in the tank to grow just about any plant i want. so do i need a 36" 2x39 or 4x39 light fixture? i'm afraid that the 5" wide 2x39 will not cover the full 18". i'm looking at the fishneedit.com fixture. also, any bulb brand and color temp recommendations are welcome.