This has never been very serious. It comes and goes with the seasons and weather. It’s easy to remove by twirling round a stick, but this tends to trap and pull out plants and animals, so I’ve stopped doing it this way. It can be pulled away from plants by hand and dumped in the shallows, where it dries out in dry periods and put on the compost heap (where it doesn’t rot down much, oddly). I haven’t had to add tap water to the pond since it was first filled, and the blanket weed is definitely in decline.