Jane,a Skippy filter is best described by information in the Skippy website. In short it is an external filter that performs as a mechanical and bio filter. Some like it and others don't. The basic component is a stock tank containing material that houses beneficial microbes and a swirling action that allows particles to be removed from the water.
Your statement that you are using an external filter and pump isn't very helpful. Do you have a problem with your system? If so, we would need to know things like pond volume, pump rate, rocks or no rocks on bottom, head(the height the pump raises the water), type of filter and fish load if you have fish.
If you don't have a problem, then welcome to the forum.

Here is a link that might be useful: Skippy Stuff

can someone e mail me some small biofilter instructions. not very good on the puter yet. fergies10@hotmail.com.
thank you for your help.