Thanks for posting about pond weed control.
Biological Control .. best seems to be Grass Carp reported to eat the weeds, we are still investigating.
Chemical Control... not allowed to use herbicide as our pond is linked to the River Itchen. However we do use Barley straw extract to control algae.
Mechanical Control ... motorised cutters etc are far to expensive and you still have to rake up the cut weeds.
In the end throwing a rake out or placed behind roots by guy in a boat and pulling it in is the best solution for us, so far. one in the boat, two each with a rake and barrow. we cut and collected barrow fulls.
We continue to use Pond Dye
(see biofix and dyofix.co.uk) other shading can be obtained by planting willow trees.
Weighted black polythene sheets
for 6 months at a time has been suggested as has solar powered fountain or air pumping air bubbles as this reduces infestations and oxygenates the water.
Regards, Tall Paul.