I am currently rebuilding my pond. It was a cheaply built 4000 G algae producer. It came with the house and the previous owner didn't do much maintenance. The filter was a poorly designed homemade contraption, the pond liner was 3 layers of black polyethylene, the pump was under-sized and to top it off, the pond was grossly overstocked. I redesigned the trash can filter, bought a larger pump and gave away over 300 goldfish that first spring. I've learned much from the mistakes of someone else and made a few mistakes of my own. I hope I can learn much more from this site and look forward to sharing my pond photos with everyone.