I have a small pond (my first) that has been in existence since March this
year. I live in Melbourne, Australia, where we have a temperate climate -
approx 35degrees F when it's really cold (for us, at least) up to about 105
degrees F at the peak of summer.

My water feature consists of a small waterfall where the water falls into a
small creek and then flows into the pond and the process is repeated. I
also have a skippy filter running all the time which seems to keep any green
algae at bay. The pond only holds about 800-1000 litres.

We are now (late November) coming into Summer and the weather is getting
warmer. We recently had very heavy rain and the pond was filled to capacity
(I take a runoff from the roof of my house, as we are currently in year 7 of
drought). When the rain filled the pond it was quite muddy and took a few
days to clear.

I have taken the runoff from the house all during winter without any
problems but now I have a problem.

The rocks in the pond have now turned quite a deep brownish red colour where
they are constantly wet and exposed to the light (they are all clean on the
bottom of the rock).

I am hoping someone knowledgeable out there can suggest a cure for this
problem.

If you would like to see photographs of the area (which has lots of trees
around) and the stained rocks you can take a look at this address:
www.noelb.com/pond/index.htm

I would certainly appreciate any advice you may be able to give.

Cheer

nb