Crying, “tuppence a basket, watercress-o!”
Kamil has built this mini combined basic hydroponics and pond water cleaning system – with a small £12 solar pump, pumping water into a tray with pebbles and watercress. The tray is slightly tilted towards the pond.
Results: the water in the pond clear after a week. Watercress: harvest once every two weeks.
Apparently, a few trays could be built up over each other on a scaffolding… to increase the growing space and cleaning ability.
(As your humble web-editor, I rarely express an opinion here – but in this case I really do have to say what a brilliant idea this is…)