so you don't think i should use lenses at all? and 8:4 ratio of blue:white? wouldi t look natural if i did 7:5 ratio of blue:white or would there be weird color patches?
What do you mean by natural? You mean an even blend of colors, so the whole tank looks a single color? If so then not having lenses of any kind will make the color more even looking.
Or do you mean a natural looking color? If you mean a natural looking color.... Do you mean the color things look at the surface of the ocean? Or the color things look 100 feet down?
Depending on what brand of LEDs you get this can vary some, but this should give you a basic color guide:
1:1 Royal blue to cool white gives a very sterile cold color.
1:1 Royal blue to neutral white looks almost 10k, About daylight colored, there will be some yellow looking light and most reefers would consider this ugly.
2:1 Royal Blue to neutral white looks fairly white with a moderate blue tint. This is currently what I would consider the "Standard" LED base build.
3:1 Royal Blue to neutral white would be a very blue color, probably bluer than most would want for a display tank, but should be excellent for coral growth, and one of the 2 choices I would do for a frag tank.
3:1 Royal Blue to warm white (either 4000k or 2700k from stevesleds) should be a warmer purple looking color. Personally if I was doing a 10 gallon frag tank I would do this, I would get 9 Luxeon Royal Blues and 3 Luxeon warm whites (2700k) from stevesleds and the $16 700mA driver and possibly (if budget allowed) 2 of the violet LEDs from rapidled.
Then all you need is a plug to plug into the wall, a small roll of 20-22 gauge wire, a heatsink/fan, some thermal adhesive and a plexiglass shield.