Here's my current idea: The pond itself is an old used bathtub. The filter is a 5 gallon bucket with small holes in the bottom and several layers of burlap as a filter agent. The pump is a fountain pump from Harbor Freight. I've used a similar one before in a turtle pond. The tube at the bottom, shown here in white is a piece of PVC pipe with lots of tiny holes in it and wrapped with a kind of plastic coarse weave cloth that I found alongside the road. Thoughts, suggestions?