[dbozkurt]

I lived in Carshalton where we have two large spring fed ponds which have had to have concrete bases since the water table dropped. In the summer months the scum, discolouration etc. is discusting from the bread. Every few years the ponds have to be emptied and dredged (water table permitting). The build up of scum can not also be healthy to both the waterfowl and the water life can it?

Debs