Posted: 16/06/2013 at 21:54
Lovely pond !!
I used to have 2 ponds in my garden. The fish pond was in full sun and always went green and a bit of a battle at times. And the wildlife pond was in shade from 11am onwards......and I could always see to the bottom of it - crystal clear water.
You should try the plank idea for a few weeks, if you don't have kids. Starve the algae of its food source, the sun. See if you can rid the water of its green hue. It might still look cloudy but with hand filtering and partial water changes this would improve in time.
No, the plank idea won't look attractive but experiments never do. It could give you a direction in which to follow from here. But don't cover the lilies or oxygenating though - they need full sun.