Where do you live, Lillie? Two feet may not be deep enough to over-winter
your fish. If you're doing koi (as the others said), you "should" have at
least 3', and more is better. If you live in an intemperate area - basically
any place that has "winter", 2' will probably give you fishsickles before
Spring. A pond 15 x 15 x 2 = 3532 gallons of water and a liner requirement
of 21' x 21' (an awkward size). A pond 12 x 12 x 3 = 3391 gallons of water,
with a liner requirement of 18 x 18' (a 20' square piece of liner would work
nicely). Or a 12' x 12' x 4' = 4522 gallons with the same 20' square liner.
Filtration is SUBjective as well as OBjective. Do you want to buy or
build???

Lee

"Jleag" wrote in message
...
Hi,

I am the proud owner of a 100 gallon pond which I have had for 10 years. I
love it and now I want to expand to a larger pond. I am building a 15' x
15' x
2' pond and need a new filtration system. Do any of you nice people
reading
this have experience in this area. I am thinking about a gravity fed
filtration
system to deal with the koi I would like to have in the pond. Any
thoughts you might have would be very appreciated! Thanks in advance for
your
help -
Best wishes and happy ponding!! Lillie