monti color fading

[emerald chondro]

On my 75g my Mh bulb burnt out (usually its 15k) so i had to replace the bulb with an older 10k...... Since the spectrum is more white then blue i expected a somewhat shift in color. However my lime green monti is starting to turn an uglier green and if this continues within a month he will be brown. My question is if i upgrade the light to 20k's will he return to his former green color?

paramaters
ammonia:0
nitrite:0
salinity: 25

[Steinsland]

My experience with higher Kelvin is that green turns to metalic green and so one. Especially blue and green color corals have that advantage. Other colors may fade away with high Kelvin.