We have a small pond in our garden, about 1-1.5 meters in diameter and it’s quite deep in the middle. We have a toddler and I’m looking for some advice on how to keep it safe for toddler. Can only think of 2 options: a net over and filling the pond with big pebbles until youngest child is old enough. Also I’m not sure what this black box in the pond is for and if I can/should remove all the roots which grow in the water. Photo attached