Algea ID please

[Willy123]

Dear All

Some type of algea is choking my buttons.
On the picture you cant really see the colour but it is kind of grey.
Grey leaves that also form mats on the substrate.
The structure reminds me the most of a camouflage net.
It forms placks on the sand and overtakes some of my corals.
I am not measuring any polutants in the water.
But if there are algea there are polutants right .

I cant find any pictures that look like this.
Regards
And greets from across the atlantic

 

[Willy123]

Better close up of a piece out of the water, and in to normal light color is not grey.

 

[JZinCO]

My first impression is dictyota..

 

[JZinCO]

As it grows from its base does it keep growing out in Y's

 

[BlueCat1949]

I would say dictyota as well. It can be very invasive and hard to get rid of in a tank with corals.