zookeeper wrote:

Thomas Ball wrote:

I think it is a great idea!

Light!(Will not hold water)
Easy to inspect! (Shine a light to look for blockage)
Easy to clean! (A little moderate pond water pressure from a hose
would push
any crud through to the bottom)
All crud will fall directly to the bottom! (bottom drain in filter?)

Might have to gasket between the straws and the container to prevent
short
circuit.


Tom, what do you mean by "gasket between the straws and the container?"


I think he means, if the water flows vertically and there's space
between the straws and the side walls then the water will flow around
the straws. What I'm going to do (I bought 25000 straws yesterday for
$45!) is fill the entire space from wall to wall with straws so there'll
be no gap that needs to be filled in. I think it'll work because the
walls are vertical.



One summer we used plastic forks as our filter media. It worked well,
but they turned out to be heavier than I had expected. Will be
interested in any feedback on using straws if anyone tries it.


Actually, straws have a different problem. They float. So keeping them
down will be the problem.

Matt

"Matt Rosing" wrote in message
...
snip
I think he means, if the water flows vertically and there's space
between the straws and the side walls then the water will flow around
the straws. What I'm going to do (I bought 25000 straws yesterday for
$45!) is fill the entire space from wall to wall with straws so there'll
be no gap that needs to be filled in. I think it'll work because the
walls are vertical.
snip

If the water flows within AND around the straws...won't you double your
surface area?

BV.

Considering a barrel filter. I was thinking that you would build a round
cartridge so all the straws stay upright and bunched together. It would have
a tension band around the outside and a top and bottom screen inside a
support grid to keep the straws from dropping or floating. The cartridge
would be slightly smaller then the container so a bit of closed cell foam
around the circumference would prevent water from leaking around the filter.


Interesting, that using the smaller 1/8" straws (7.75" long) nets over 500
sq.ft./cu.ft. density! (Although you use 4 times as many, about 65,000 in my
calculations, they are still cheap compared to foam)

May Matt have found "the perfect filter"? (engineered media rather than
random)



Tom

"zookeeper" wrote in message
...
Thomas Ball wrote:
I think it is a great idea!

Light!(Will not hold water)
Easy to inspect! (Shine a light to look for blockage)
Easy to clean! (A little moderate pond water pressure from a hose would
push
any crud through to the bottom)
All crud will fall directly to the bottom! (bottom drain in filter?)

Might have to gasket between the straws and the container to prevent
short
circuit.

Tom, what do you mean by "gasket between the straws and the container?"

One summer we used plastic forks as our filter media. It worked well,
but they turned out to be heavier than I had expected. Will be
interested in any feedback on using straws if anyone tries it.
--
zookeeper

Andrew Burgess wrote:
One summer we used plastic forks as our filter media. It worked well,
but they turned out to be heavier than I had expected.

Hey, good idea!
What do you use now?

We are now using the strapping "tape" or plastic strips (~1/4 inch wide)
that are overlapped and heat-sealed to secure boxes or bundles or loose
items. We get ours from the newspaper bundles for the boys' paper route.
It was a free, reusable substitute for filter "ribbon" or Springflo. You
might also be able to buy the tape from packaging product companies.

Other small, light-weight plastic filter materials: forks, tubes from
rolls of adding machine tape or adhesive tape, PVC pipe (small pieces,
or one ponder cut his PVC into 1/4-1/2 inch spirals with a lathe and a
blade set at a slight angle), dish "scrubbers" (typically orange/white,
blue/white -- buy in bulk from Costco, Walmart or on line), quilt
batting or other nylon / plastic based "stuffing" or "filling" (large
cell foam), nylon window screening (easy to "swish" clean); etc. Just
about anything with holes, grooves, indented surfaces that water can
flow through without any impediment. Don't use something like plastic
bottle caps because that creates "dead" areas where water can stagnate
or other materials where the water can create channels that bypass the
filtering ability of the holes, grooves, indents. The other thing to
look out for is that whatever material you use can't have any built-in
antibacterial or antimicrobial treatments (some furnace filters, some
quilt batting, some foam). Any of these smaller plastic items can be put
into mesh laundry bags, then the bags placed in the filter. That way
they're easier to swish and clean or hose off with declorinated water,
and it's easier to create layers that cover the entire barrel or box so
no water goes around the filtering material.
--
Kathy B, zookeeper
3500gal pong (Oregon)