This sounds like a workable solution for the rock bottom ponds. It would
work much more like the undergravel filters of aquariums since you would be
pulling water through and then filtering, etc. One caution would be to put
sufficient support under the grates to be able to walk on the rocks.You
never know when you will have to get in to rearrange pots, catch fish, etc.

Yes, you really need to use some kind of support pallet for this.

I'm not really trying to turn it into a filter; just a single layer of
hand sized flat-round stones. There will be sufficient gaps to allow
certain kinds of wild life to live, hide under the "false bottom".

I don't think detritus will accumulate down there; a mild pull will
exist from all times from the bottom drain...

C//

"Courageous" wrote in message
...

I don't think detritus will accumulate down there; a mild pull will
exist from all times from the bottom drain...
========================
Wouldn't these small critters like tiny chorus frogs, pollywogs and newts
get sucked into that bottom drain?
--
McKoi.... the frugal ponder...
My Pond Page http://tinyurl.com/cuq5b
~~~ }((((o ~~~ }{{{{o ~~~ }(((((o

Wouldn't these small critters like tiny chorus frogs, pollywogs and newts
get sucked into that bottom drain?

Possibly. It's a large pipe. It's 3600 GPH through a 4". If it's too much,
they'll end up living in the settling tank. :-)

C//

On Thu, 04 Aug 2005 07:51:43 -0700, Courageous
wrote:


Wouldn't these small critters like tiny chorus frogs, pollywogs and newts
get sucked into that bottom drain?

Possibly. It's a large pipe. It's 3600 GPH through a 4". If it's too much,
they'll end up living in the settling tank. :-)

C//
Hi Courageous,
I've been trying to think how to construct a rather large screen dome
to place over the BD to address this problem. ("Large" = reduced
suction per sq.in. = small critters (and fish) can escape more
easily); but screen grid still large enough to permit mulm to pass
thru.

Or perhaps concentric domes of decreasing grid sizes(?)

It's a difficult question isn't it? -- trying to solve two intertwined
but mutually exclusive problems at the same time!

Do you think it's worth experimenting?

I've been trying to think how to construct a rather large screen dome
to place over the BD to address this problem. ("Large" = reduced
suction per sq.in. = small critters (and fish) can escape more
easily); but screen grid still large enough to permit mulm to pass
thru.

Or perhaps concentric domes of decreasing grid sizes(?)

Unnecessary complexity.

It's a difficult question isn't it? -- trying to solve two intertwined
but mutually exclusive problems at the same time!

Do you think it's worth experimenting?

Sure. Why not?

I think that you might start with:

1. Perforated PVC sheet.
2. An ability to draw a circle and cut it cleanly.
3. A dome (to place your hot pvc over, to form it)
4. A heat gun.
5. Elbow grease, safety precautions, and common sense.

I think you'll do fine, and the fabrication won't be as hard as you
think. Here's what you're looking for; it's probably expensive, and
if you hunt locally you'll be able to get it for less:

http://www.usplastic.com/catalog/pro...uct%5Fid=10081

Also, since you are thinking of novel screening solutions, you may
find this interesting:

http://www.aquaticeco.com/index.cfm/.../8559/cid/2079

Note that it is ever so slightly flexible (firm but somewhat soft). Not perfectly
rigid. It may get slighty deformed in shipping (mind did), but is easily straightened
with heat application (such as slipping it over 4" PVC and putting it in the sun).

C//

Courageous wrote:


Do you think it's worth experimenting?

Sure. Why not?

I think that you might start with:

1. Perforated PVC sheet.

Oh? Thanks for that link - I've never seen this stuff but pre-perforated
PVC sheet would be really useful for a project I have in mind...

2. An ability to draw a circle and cut it cleanly.

Uh-oh! That leaves me out :-)
--
derek

On Thu, 04 Aug 2005 19:02:20 -0700, Courageous
wrote:


I've been trying to think how to construct a rather large screen dome
to place over the BD to address this problem. ("Large" = reduced
suction per sq.in. = small critters (and fish) can escape more
easily); but screen grid still large enough to permit mulm to pass
thru.

It's a difficult question isn't it? -- trying to solve two intertwined
but mutually exclusive problems at the same time!

Do you think it's worth experimenting?

Sure. Why not?

I think that you might start with:

1. Perforated PVC sheet.
2. An ability to draw a circle and cut it cleanly.
3. A dome (to place your hot pvc over, to form it)
4. A heat gun.
5. Elbow grease, safety precautions, and common sense.

I think you'll do fine, and the fabrication won't be as hard as you
think. Here's what you're looking for; it's probably expensive, and
if you hunt locally you'll be able to get it for less:

http://www.usplastic.com/catalog/pro...uct%5Fid=10081

Also, since you are thinking of novel screening solutions, you may
find this interesting:

http://www.aquaticeco.com/index.cfm/.../8559/cid/2079

Note that it is ever so slightly flexible (firm but somewhat soft). Not perfectly
rigid. It may get slighty deformed in shipping (mind did), but is easily straightened
with heat application (such as slipping it over 4" PVC and putting it in the sun).

Thanks C//,
In my mind's eye I have been looking for products like both of these!
And great ideas for fabrication!
David

"Courageous" wrote in message
...

Wouldn't these small critters like tiny chorus frogs, pollywogs and newts
get sucked into that bottom drain?

Possibly. It's a large pipe. It's 3600 GPH through a 4". If it's too much,
they'll end up living in the settling tank. :-)
=================================
That may work if they don't have to get past the impeller to get there. You
may find your settling tank full of critters in a few days. :-)) I find
pollywogs in my settling tank at times. I don't know how they get past the
"clam-basket" the pump is in.
--
McKoi.... the frugal ponder...
~~~ }((((o ~~~ }{{{{o ~~~ }(((((o
http://www.hyphenologist.co.uk/killf..._troll_faq.htm