Hi guys, Ive had this green hair algae since starting the tank a few months ago. (I know there's going to be algae for awhile after starting a tank). But, it's gone off of every other rock except this one. The others have been green hair algae free for about a month now and this one just persists. It's only this rock, all others are algae free and starting to get covered with coralline. Any tips on how I can get this stuff off and get the coralline to take over this rock also? Or is it just a matter of time?