It's probably DOC (Dissolved Organic Carbon), or the visible results of
overfeeding, perhaps the need to clean the pond or filters, etc. Water
changes can help; I also know people that have used food grade liquid
silicone to change the surface tension of the water so the foam goes away.
This is a neat trick to use 2 hours before a house full of guests shows up
and you want the pond to look its best, but the *best* way of taking care of
the problem is to, well: take care of the problem. Clean the pond/filters if
necessary, cut back on feeding and do some water changes. It's harmless, but
unsightly.

Lee

"ba5416" wrote in message
ble.rogers.com...
I live about two hours north of Toronto Ont. I have a 3 yr old pond about
a
1000 gallons or so. Healthy from the beginning. There are about 10 fish in
there and I have had successfull breeding since the first year. The
deepest
part of the pond is about 46" deep and I leave the pump running throughout
the winter as I leave the fish in year round. There is a fountain on the
pump and a water fall at one end. The waterfall rock is limestone that I
collected from an old fence line.

My problem is this year I am getting foam buildup from the water fall. Did
not have the problem last year but this year it is bad. Water tests that I
do indicate that everything is fine for all the important things like PH,
nitrites, nitrates, hardness etc.

The local store is at a loss why the foam. They have done tests as well
and
have not found anything bad. I have seen foam on rivers which says to me
it
is something natural, but it looks terrible.

Any suggestions???