I have a pond that measures about 5 feet by 3 feet, is there a way of
keeping leaves out of the pond whilst letting wildlife in and out? At the
moment I have a net over it weighed down my bricks, stones & plants with one
corner in the most sheltered area raised by a couple of stones... is there a
better method as leaves still find their way in. Also, if I add some water
snails is there a certain number I should aim to keep their population below
to keep the toxins down from their waste?

TIA

Dave