Coral coloration and growth in my tank

[ReefRockerLive]

Today I tested my water levels and it came out to the following:

pH-7.97(ph Monitor reading)
Nitrate-?(Ran out of tests)
Nitrite-0
Ammonia-0
Phosphate-0.15
Calcium-415
Alkalinity-8.3 DKH
Salinity-1.023

I have a 75g tank w/2x400w MH(one 15k XM) (one 20k XM)

Coral coloration is acceptable under the 15k and a little better under the 20k.

If my levels above are fine then shouldn't my coral growth and coloration be good? At the moment they are acceptable, but not great. I am not using Zeovit yet, but will soon. I just want to see how much color I can get out of the corals before I begin the process.

Could the problem be comming from my 400w 15k bulb? Is it possible that my corals don't like that kind of spectrum?

Thanks

[fkadir]

Try to work on the PO4. 0.15 is very high compared to the targets of >0.04. IMHO, Zeovit is the way to go to drop the numbers in a slow and steady manner in a very safe way.