Oh, it has to be in the tank in the first place.
How can it be only on the wood and not in the tank?
There are numbers of them (algae) already in EVERY tank, just in dormant.
The question still not answered, c'mon, I'd like to know.
Is there a guideline to maintain the wood algae free?
Less ferts in water column?
Or we all have to scrub here, Excel there every week?