I want to expand to a larger pond. I am building a 15' x 15' x 2' pond and
need a new filtration systemI would highly suggest looking into a bead filter
with a UV sterilzer. Not because we sell them, but we sell them for a
reason... (after 10
years building and servicing ponds).

That isn't such a big pond, and you really do NOT NEED big filters and uv's. I
run a 13,000 gallon koi pond on just a veggie filter and lots of plants in the
pond. Since you have not built it yet.... Might I suggest you make the pond (
or at least part of it) 3 feet deep instead of 2....much better for koi. They
need the extra depth to properly excercise some of the mucsles that can only
be excercised by diving deep. Jerri

http://www.fringeweb.com/Ponds/JerrisPond