I have built one where the water flows in from the top via a spray bar, through foam matting and filter material. The return pipe comes vertically from the near the bottom of the tank, bends 90 degrees near the top of the tank and returns the water to the pond. Question:How far from the bottom of the tank should the bottom of the pipe be, and should ther be any holes drilled in further up?

be sure the return pipe is a large diameter and frankly, it works better to plumb a
biofilter in reverse, the input at the bottom, the output at the top just because
"crud" can settle on the bottom easier. OTOH, it IS easier to lift the coarse filter
off the top to clean it, but if you have an valve at the bottom that can be opened
then the whole thing is easy to clean out.
you not only need holes to make sure it doesnt clog, the more holes the less suction
at any one of them. Ingrid


On Mon, 24 Sep 2007 15:18:02 CST, bob29 wrote:


I have built one where the water flows in from the top via a spray bar,
through foam matting and filter material. The return pipe comes
vertically from the near the bottom of the tank, bends 90 degrees near
the top of the tank and returns the water to the pond. Question:How
far from the bottom of the tank should the bottom of the pipe be, and
should ther be any holes drilled in further up?

wrote in message
. com...
be sure the return pipe is a large diameter and frankly, it works better
to plumb a
biofilter in reverse, the input at the bottom, the output at the top just
because
"crud" can settle on the bottom easier. OTOH, it IS easier to lift the
coarse filter
off the top to clean it, but if you have an valve at the bottom that can
be opened
then the whole thing is easy to clean out.
you not only need holes to make sure it doesnt clog, the more holes the
less suction
at any one of them. Ingrid
================================
I would think this would put some serious back-pressure on the pump as the
filter material caught the crud and slowed the flow of water.
--

RM....
Frugal ponding since 1995.
rec.ponder since late 1996.
Zone 6. Middle TN USA
~~~~ }((((* ~~~ }{{{{(ö

We ran our water in the top of one end of the veggie filter and out
the top of the other...after slowly moving through the roots fo the
plants. The water hits the bottom as it enters and slowly filters
through the filter, leaving junk on the bottom and exits at the top.
We don't have a mechanical filter to clean.

Jim

"Phyllis and Jim" wrote in message
ups.com...
We ran our water in the top of one end of the veggie filter and out
the top of the other...after slowly moving through the roots fo the
plants. The water hits the bottom as it enters and slowly filters
through the filter, leaving junk on the bottom and exits at the top.
We don't have a mechanical filter to clean.
=======================================
That's a good setup. We have the one veggie-filter-settling-tank. The water
enters at the top back and slowly moves forward to the two outflows, also at
the top.... the crud, loads of it, ends up in the roots and on the tank's
bottom. I just remove the plug at the bottom once in awhile and flush it
out. No back pressure on the pump.
--

RM....
Frugal ponding since 1995.
rec.ponder since late 1996.
Zone 6. Middle TN USA
~~~~ }((((* ~~~ }{{{{(ö

We're right with you on the design. Pretty safe and very easy to
clean out.

Jim