I've recently noticed stringy gray/white algae on my plants - primarily on my wisteria. I haven't seen algae like this before...what kind is it and how can I prevent it? It's a 10 gallon tank, and I do water changes on a weekly basis, last time I had my water tested for phosphates, there wasn't a problem. It's the only algae in the tank at the moment. Any information you have is greatly appreciated