Hi John,
You have a great plan!
More information is better, so might I suggest
you read through some of thie info on the following link.
Lots of good concepts for DIY filters of all sizes.
You may want to reconsider the lava rock (very heavy
and it clogs up quick), and the metal rack for
supporting your media (It'll corrode in time).

http://www.mikebentley.com/ponds/homemadefilters.htm


HTH,
Mark

"John" wrote in message
m...
My fellow PORGS:
I am designing my filter for my 6000 gallon's pond, i am thinking
about the following.
1) build a 3x4x5 filter


water in

| |
water out | |
-----------------------|--|
| | |
| Water Hy's | |
| | |
-----------------------|--|
| | |
| filter material | |
| (lava rocks,foams etc| |
| | |
----|---|-----|----|---|--|
| | |racks| | | |
| | |space| | | |---
| | | | | | |---|
valve to flus the waste out
-------------------------


a) using EPDM liner for inside, I am debating concrete bricks
or plywood (outside) with strong Simpson Tie (supported by lots of
rock), has anyone create such a big filter with plywood? will it be
about to hold such volumn?)
b) I will put a 10'' to 1' tall rack on the bottom of the
filter ( for all the dirt debris)
c) make a hole on the botton of the filter, connect it with 1
1/2' PVCS pipe, end it with a valve, (to clean the filter,flush out
the waste )
d) put some iron mesh on top of the rack
e) put lava rock & filter material on top of the rack
f) put water hynache on the very top
g) install a 4' pipe from top done to the bottom of of the
filter with some open on the bottom, running my 1 1/2' pipe(from the
pump) inside the 4' pipe.

2) the clean water will flow out of the filter to 2 fall's (1' per
fall)
3) the water will flow to a 10'x4'x(1-2)' veggie filter. again, I
am debating using concreate block or plywood to build this
3) the water will flow from the veggie filter to the pond
Please comment
Thanks for any input, ideas.
John