Coral color Fading.

I need some help.I have a few sps that seem to be losing color.I give you a little backround:Tank was setup in 8/11-75 gal.The live rock I've had for a few years and moved from system to system-about 90 lbs.I know my po4 was very high-1.03 ppm and it is now down to .12 so I'm still working on that.Temp is steady between 75-77 daily.Nitrate is 0 ppm per red sea kit-I trust this result.Mag-1400,Calc-440,KH 12.6,Sal 1.026.Lighting is an 8 bulb sunblaze t5 54 watts/bulb.Photo period was from 8 am to 8 pm with coralvue moonview for night time viewing.Yesterday I cut the photo period back to 2pm to 8 pm.It just seems to be a few corals from high to low placement in the tank.I was dosing red sea nopox to try and combat po4 and I believe this is when my problem started.At the same time I increased my photo period.Could my water be so much cleaner from the nopox the corals are getting more light now or do you think it most likely from the increase in the light duration or something I'm not thinking of?For the last 2 days I have not dosed the nopox and as stated I cut the photo period back.
Thanks for the help,Daniel

 

12 hors is a pretty long photoperiod I would think they might be bleaching. However, I've had problems with pale corals from having very low nutrients as well. Seeing as the problem started with dosing throttle it back a little bit and see what happens?

 

I was think that as well but I've also been feeding red sea nutrition and also wouldn't all corals be fading from low nutrients?

 

Probably a combination of the two. The quickest safest way to is try cutting your photo period from 12 hours to 10.

 

Done.Thanks

 

Anyone else care to chime in?

 

Daniel, I think you have answered all the questions your self already ( I am not surprised).

Reduce the lighting time and cut back on the additives. I believe you probably made too many changes at once, cutting out the phosphates always good, too long of a lighting period at once and and possible a reduction in available nutrients for the corals current zooxanthellae.

I hope that helps a little. I believe you are on the right track though.