HELP PLEASE what is this

[DanielN30]

Hi I appreciate your time to look at my post but is this algae or some sort of fungi I have no idea myself.
Its the white patch the black is shadowing


Many Thanks Dan

 

[Delapool]

Is it on the wood? If so I would suspect fungi.

 

[Fishey bricks]

I agree, I seem to always get this when I use hardwoods in my tanks. For me it usually dies off after the tank has become established, but if not you can remove it by hand. Or maybe try spot treating with some Excel.