Lighting question- Lps seem to be losing color

My sps seem to be doing well but all my other corals lps mostly seem to be loosing color especially the purple orange red pink and yellow colors, I am currently running a 6 lamp t5ho ati sunpower on a 72 gallon bow front (tanks about 18-20 inches depth) fixture sits 3 inches above water level. All water parameters are checked regularly and all are optimal. Bulbs are all fairly new and as follows from front to back...

Ati blue plus
Ati blue plus
Ati blue plus
Hagen life glo 6500k
Ati blue plus
Ati aqua blue special

SpS more toward back is this reason for aquablue being placed in the last slot

Could it also be that I have been using kalkwasser in my auto top off?? I defenitly realized ever since I started using the kalk instead of TLF two part my coralline algae on my rocks has died out a bunch but maybe this could be because of the lighting and not the kalk, I had better pink and purple coralline growth when I had a 4 bulb fixture that was giving off minimal light due to bad reflectors.... PLEASE VOICE YOUR OPINIONS ALL COMMENTS AND SUGGESTION WILL B GREATLY APPRECIATED!! Thank you

 

ASSUMING correct water parameters, its most likely too much light. Coralline algae will die off in excessive light. That is a very powerful light. It can be difficult to make everything happy in a mixed reef.

 

I'm thinking too little light?

I don't know exactly your light specs, but if 5/6 of your Bulbs are 'Blue'... i'm' assuming their in the Actinic spectrum of light... which means their only prompting the corals to utilize photosynthesis, not offering the spectrum of light actually needed for corals to photosynthesize.

And your 1 bulb that is 'white' is 6500k, which is more the spectrum you want for freshwater plant photosynthesis, not coral photosynthesis.

You would be better off with 2-3 bulbs of 10,000k, or 14,000 (i'd go with 10,000).

 

I agree with this. I have a similar fixture and bulbs, and just recently suspended it ~14 inches over the water. My frogspawn has gotten a much deeper green color than before, which was almost a translucent light green.

If your coralline has lightened or turned white, your light is too intense. It's bleaching...