Why are you stuck on LEDs. You can get quality t5 fixture for that tank and have colors that are through the roof. For a 40 breeder you could get a good quality Tek or ati fixture used and it would be far better then any LED
you could ever buy. You could even get any other 6 bulb t5 and be better off. The fixture on eBay are nice for a budget, but the color needs to supplemented with other LEDs or t5 to make colors really come out. Mind was nice because it was custom made at Apollo LEDs and had 3blues for each white. So color was nice in the 20k range. I have seen the 14k LEDs and its pretty yellow IMO
. You would need t5 to supplement.