Is this an algae growth or something else

[Dizzy]

Is this an algae growth or something else?
Since day one the wood has had something growing on it starting with the usual slime from the sugars and other goodies leeching from the wood, to being carpeted in some brown and green forms of algae, which I found pleasing as did the snails and shrimp.
It all seemed to die down once the plants started growing (hygrophillia polyspermy and Valis ) but I've now got this white growth, hasn't seemed to affect anything. More curious than worried.

 

[DaveWatkin]

Not seen that before. Was it always white? Looks like something that has died off and turned white.

 

[Dizzy]

There was patches that looked the same, but green and brown. Could be dying off I suppose, although nothing else in the tank whether algae or plant is looking sickly or dead