Utter choas question

[greyhunter]

I got this utter choas frag 2 months ago. It started as the 2 really bright orange heads. The new heads look way less orange then the original ones. The oldest/biggest new head is a month old and still not very orange. I had 0 phosphates for a while recently (week ago) i managed to bump them up to 0,05. Could that be the reason the are dull and they will start to color up now?

 

[Catawba_Valley_Reef]

Low po4 could be it, but it could also be that they are babies and will color up more as they grow/mature.