I bough the java fern a couple of months ago and I tied it to this drift wood. a couple of months later there was this growing on top of it, just a tiny bit. so I removed it, or at least I thought I did. Now it is growing in the whole tank, including the substrate and I don't know what to do. It is actually way more difficult to remove that I though, it is attaching firmly to the driftwood. Any indications?