LED color combo ratios

[Flame_Angel]

Is there a good, basic formula for determining a ratio of blue to white LEDs to achieve a certain color? For example, what ratio would give you a 14k, or a 20k color? I'm looking into retrofitting a 14g BioCube (assuming 12 LEDs), and I'd like to get into doing SPS in it. Would 20k be a good color for this, or would I be better off with a lower color number?

[mordibv]

2 to 1 ration RB to CW or NW for 20k .
If you use dimable ballasts color is not an issue . U can make them the color you want .

[ndh78]

I just made my own fixture for my BC14 and used 12 cree rb and 6 cree cw. although I have them independently dimmable I think it is a good combo. I like 14k phoenix halides if that gives you an idea. Btw I am very impressed and will likely doe led builds for my bigger tanks now.