I've been cleaning it when my water spitter starts to
get clogged and doesn't shoot up as high, but that's not very often

Thats a good way to know when it needs cleaned.

And to reiterate my other post--do I need to fertilize my water lilies to
get flowers?)

Some say yes, and some say no. I for one say yes. But each pond is different
so everyone has to find the best thing to do with their own pond and plants.
Jan
"Our Pond" Page
http://hometown.aol.com/pinkpggy/index.html