Depending on the type of pump you use, I use the pre filter with the 1/4
rabbit wire mesh made using this link. I don't clean it all summer.
Anything smaller than 1/4 inch is not going to hurt my impeller.

http://www.perigee.net/~jrjohns/web20.html

"RussellinMD" wrote in message
om...
I live in Maryland and my pond is about 5 years old. Last summer I
had to clean the pump filters once a month as they would get so
clogged the water falls would stop. I replaced the UV bulb last
summer and have inserted new filters with no improvement. What can I
do to prevent this from re-occuring this year?