Steve wrote What
is the reason for having a filter?

Often a pond can do fine with lots of plants and a waterfall over rocks.
Problems happen when the original fish grow larger and then breed and over
populate the pond.

The mechanical part of the filter can catch a lot of gunk and that helps with
green water. The biological end of the filter helps when the pond's inhabitants
overtax the natural system.

If you keep the population down, clean the pond every year you'll probably be
fine. Just to be sure you can purchase a water test kit from your local
petstore that sells fish and see what your numbers are.


kathy :-)
algae primer
http://hometown.aol.com/ka30p/myhomepage/garden.html