I skipped a water change last weekend on my 20long and I've got got 5 healthy jungle vals in the tank. I just did a water change and noticed that on some of the leaves that were a little brown had some tiny hairs on them. I rubbed on the leaves and the brown came off but the hairs were still there. Is this the plant itself? What do I need to do to prevent a brown algae bloom like I had on my other tank?