The underwater plants - so painstakingly planted by me - are growing. In some areas of the pond they have already reached the surface of the water. This is a good sign - they are generating oxygen all the time and I can see the bubbles rising. Judging by the pattern of growth, the plants grow best when they are near to the points where water is recirculated, which seems logical. I am keeping an eye on some areas though where nothing much seems to be happening and have some spare plants in a tank just in case.