Mine never gets any algae on it in my 150 between the little flagtail on one side of the divider and the bigger flagtail and 2 small gibbys on the other side, but if it did, I'd leave it. I think the algae makes the driftwood look even more natural. Actually, my 29 gallon has at least 3 different types of algae growing on it and it looks awesome, especially the little tufts of BBA