Normsally sand is not so good of an idea, from what i read and hear
anyway as its prone to packing in some areas and containing debri
which leads to aernomas(sp?) building up. Eventually it will clog in
some areas and channels will start to form, which is the only area
doing any kind of filtering.......which leads to dead spots
internally. When sand and even coarser gravel is used, normally a high
head pressure pump is used so it can make the sand suspended somewhat
and even then it will clog and pack.Water is normally forced thorough
them instead of pulled through. Thats why they use beads in these type
of filters when used in ponds with low head pressure pumps, so they
are somewhat bouyant, and not prone to channeling. Its still common
to have a means to backflush the entire item to get rid of any buildup
detris which reduces any chance on having a aeronomas getting
established. I have three of the large swimming pool tanks / filters
and had intended to do basically what you have done, but too many
folks in other forums voiced opinions in regards to potentials for
problems if no backflush is available or from channeling setting up,
so they set here unused.........Thats one reason a swimming pool has
such high flow and pressures as compared to pond setups, as it needs
to be able to break up and flush the sand so they do not channel etc.
Usually aeronomas are not a problem in a swimming pool as they use a
chlorine to control problems.........But hey if it works for you
great.....just keep an eye on it.


On Sun, 20 Mar 2005 01:46:01 GMT, "George"
wrote:

===
==="Hal" wrote in message
===news:5qbo31dnm72g56a5madl7ur2r6vu3f7fot@4ax. com...
=== On Fri, 18 Mar 2005 21:26:23 GMT, "George"
=== wrote:
===
===My brother has a large partially in-ground swimming pool. He forgot to drain
===the filter one winter, and the water froze and broke the backflush valve.
===Because of its age, he decided to buy a new one instead repairing this one, so
===he gave it to me. I just needed the tank itself, so I stripped out the guts
===and
===converted it into a biofilter.
===
=== So what you have is a pool filter with a more coarse medium than
=== sand?? I often wondered how that would work.
===
=== Regards
===
=== Hal
===
===No, I have a former pool filter that has been gutted of all its parts,
===retrofitted with a basket strainer in the bottom, filled half-full with
===medium-coarse gravel, and a pump mounted in the void above the gravel and
===connected to a kevlar plate which is bolted to the top of the filter housing and
===the top opening. The pump outlet and electricaly is fitted through this plate.
===The entire unit is submerged into the pond, beneath the waterfall at one end.
===When the pump is on, it draws water into the filter from the bottom of the
===filter, which travels through the basket strainer and the gravel, then is pumped
===back out over the waterfall and into the pond. The intake of the filter is
===connected to a 6 feet long hose which is connected to a pre-filter which is
===situated right in the middle of the bottom of the pond.
===


==============================================
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