Sounds like a bacteria bloom, if it is a milky white cloudiness. Stop
cleaning the pump sponge, unless it is restricting water flow? Are there
fish in the barrel? If not, you can probably take off the sponge. ~ jan


See my ponds and filter design:
www.jjspond.us

Thanks Jan
I'll give it a try.
It seemed quite smelly and had what looked like a film on the surface as
well as the foam.
I don't want to put any fish in while it's like this.

Peter