Blanket weed is a never-ending problem in a pond. I used to use a wide-headed rake thing to drag it out. It's aptly named. The green 'blanket' was amazingly thick. One leaves it on the grass around the pond to give any wild life a chance to hop back into the water. Then about a couple of days later one can dispose of it.
But I got a good tip from a TV programme of putting a small barley straw bale into the pond. (One can get miniature ones) It will float about and in some mysterious way stop blanket weed and also render the water clear.
Some beautiful fallow deer often came to drink at our pond, but they would go in for a paddle and their sharp hooves pierced the liner. The water level descended and had to be topped up. As we were on a water metre, this wasn't good...