How to keep distinctions?

[djscribz]

Well i have a bunch of true lineaged zoos, but they are all losing their distinguishing marks.

My RPE lost the purple rim around the mouth
My Aquaman blue lost the black strip across the mouth
My lunar eclipses are turning grey instead of keeping the purple.

they are all 20" away from the light of a 150w HQI 20k Ushio.

 

[msman825]

how old is your bulb, and how big is this tank lit with just 1-150 20k

 

[djscribz]

the bulb is 3 weeks old, the tank is a 20g + 20g sump. the display is 18" tall and the light sits an additional 2-3" above that. It is about 4-5" from the water.