Looks like the stuff that grows on new wood for the tank but since it is on rocks and plants, must be something different. For the stuff on new wood, I just let it go and the food supply runs out and it goes away. But for this, I might first try to reduce the volume. Is it a sort that can be wound up on a small brush like a round round bristle brush like we might use to clean test tubes, etc.? Maybe try grabbing a bunch on an old toothbrush to pull it off, if it will without damage to the plants. Then when reduced, I would look at spraying something like peroxide to kill the remaining. Easy so not to get too much in the water to kill/damage plants or fish.
Of course, being home, you will be picking up the tank work a bit?? Nature has a way of finding our faults when we turn our head for a minute!