Zoas take on strange shape.

[WereAllNegan]

Not sure why some of my Zoas are doing this, maybe some one can chime in. My parameters seem to be fine yet some of them take on this mushroom shaped stalk and others an umbrella shape which is usually associated with high light conditions. They're currently sitting under 100-120 PAR which isn't considered high IMO. I don't house crabs or shrimp that could be irritating them and yet to see any signs of Zoa pox.

While Zoas tend to loose some of their color with time in this tank, they do grow bigger in size. Some almost twice the size of when I originally purchase them. Its this strange shape they've taken on recently that has made me curious.

My nitrates are 10
My phosphates .04
Alk is 7.5 (salt mixes in @ 8.0)
Mag, Ca and trace elements should be within normal ranges since I do about 50% water changes weekly to keep up with Alk consumption.
Flow is moderate to medium
I don't run carbon or Phosphate reducers of any kind.
No sump or skimmer.
Just flow, heat and light.

Any thoughts? Thanks in advance

 

[vetteguy53081]

May be too much light or water flow but hard to tell without pics preferably under white lighting

 

[Cell]

Search umbrella syndrome.

 

[WereAllNegan]

I think I finally know what happened to these Zoas. When I purchased them I must have placed them in lower PAR that they were accustomed to, they began to stretch indicating they needed more light and while raising my lights to a more adequate PAR they're stalks began to shrink. Creating this effect. Just wanted to share this in case anyone had the same problem