Chris go to rec.ponds newsgroup and you will find many there that can answer
your question.
Cathy

"Chris D" wrote in message
...
I have recently installed a waterfall around my garden pond. I have
noticed
a build up of foam in a thin layer in the pond. The foam seems to persist
for hours. Is there any way of reducing this. Obviously I expected a few
bubbles around the base of the fountain but not this much.
The pond is about 1500 gallons, and holds 24 goldfish and various plants.

regards

Chris D