Over the last few weeks balls of furry looking brown algae have been growing on my driftwood, and only my driftwood. No signs of this anywhere else in my tank, not on the glass, rocks, plants, or anything other than the wood. I have live plants and my light is on for around 10 hours a day, the only chemical I use for my plants if leaf zone. Also noticed some furry green algae in two spots, doesn't seem to be growing as fast as the furry brown algae. Anybody know what the cause of this is? Thanks