Nirvana Zoas turning Pale and shrinking

[NeveroddoreveN]

Phos: 0.02
Nitrate: <0.25
Alk: 9
Salt @ 36ppt
Very high flow

They've grown a lot over the last 9 months in these same conditions but the last few weeks they have been pale and irritated. Params have been stable. I recently increased my violets (420nm) but all other zoas are doing great. Is this what too much PAR looks like for zoas? Have you seen something similar?

 

[carmodpg]

Check for pests, I have had the exact same issues with mine before. Turns out they were being bothered by asterinas and spaghetti worms.