lighting and sps

[kikireef]

So I am somewhat new to the sps game and still learning A LOT. I have a 6 bulb T5 retro kit. All sps have shown good growth and good color but not great. The colors are distinct however I have noticed that I have recieved a few frags in the past that have very deep vibrant color and that color seems to fade a bit in my tank. They all grow and keep color (no browning or bleaching) but I can't seem to keep their deep vibrant color. I have been dosing AA's which seems to have helped get me where I am at currently. My bulb setup is this
Front:
ATI Blue +
KZ Fiji Purple
ATI blue +
ATI Aquablue special (12k)
ATI blue +
ATI blue +

It has a 20k(ish) apearance to it. I have heard that brighter light will help bring out the colors better. Is there truth to this? What I am thinking is replacing one of the Blue+ bulbs with another 12k bulb. What are everyone's opinions here on doing so besides the potential better growth rate? Should I be looking at other causes? My nitrates and phosphates are undetectable using a Salifert kits. My goal here is to get some deeper colors and create a more vibrant and vividly colored reef. Any help would be great

 

[kikireef]

Here are all params in case people are curios
Ammonia, nitrite, nitrate, phosphate - undetectable
Salinity - 1.026
Alk - 8.5
Cal - 400
Mag - 1250 last time I tested which is a little low

Everything is very stable using ATO and dosing pumps for alk/cal

 

[str8leg]

You'll need to lower you Kelven output for better growth and color... remove 1 or 2 of ATI blue and replace with 10k... IMO

 

[kikireef]

bump...Ok I just ordered another 12k bulb. Anybody else have any input?