Identify and removing algae

[Xxflounderxx]

Hello,

Not sure what this is and its all over!!

250 gallon fish only
Nitrate 25ppm
Alkalinity 9.5
Salinity 1.026
Phosphate .08

 

[Benjammin]

I think it’s a type of sponge.

 

[ATAquariums]

Doesn’t look like algae. Sponge or maybe a type of anemone. Would be concerned to f with it and cause it to spread