what the... is on my GSP?

[Icefire]

Sponge? I had 3/8" thick mat growing under it 1 month ago. Now it take it over.

 

[tangyreefer05]

I am not sure, interesting pic, here's a bump for you.

 

[samherston]

Looks like some type of Sponge growing!

 

[Phoric]

I have noticed white areas growing on GSP mats before, in your case it could be a sponge, but I think the purple mat grows white stuff on it when sections of the mat die off.

 

[AquaReeferMan]

Thats a sponge. I get spots growing like that every now and again. Try and remove it or it will over grow the colony.

 

[Icefire]

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