On Thu, 27 May 2004 21:56:06 GMT, blade wrote:

Need some advice, I'm upgrading my multi bay filter but cannot decide
on a Nexus or a bead filter.

I need advice on which one is best. I have heard positive reports on
both, but they do cost an arm and a leg so I want to get this right
before I invest.

I'm assuming the Nexus you are referring to uses an Answer and is not
the one with a filter sponge.

The waste in the pond isn't really solid like grit is and it can
squeeze through holes smaller than it. The Answer is a single layer and
I would expect more waste to squeeze through than with a bead filter
which is effectively multiple layers. It all depends on whether the
spraybar on the Answer comes around before the waste can squeeze
through I suppose.

I've been playing around with a home made self cleaning filter similar
to the Answer using 100 micron stainless steel mesh as the filter media
with the spraybar driven by a spare 3000l/hour pump. Unfortunately I've
only put it around a 100mm pipe which doesn't give me anywhere near the
surface area of the Answer and with the string algae dying off now it
does get clogged. Version 2 will use a much larger pipe when I can find
something made from a plastic I can solvent weld :-)

I've got some Kaldness media in the old filter tank and the water from
the mechanical filter jets this around. The jet is above the surface so
takes some air down which bubbles back up through the media. It really
is an effective bio filter and RichToyBox is right in saying have both.
If you have the space, and money, have a bead filter (with air blower
backflush) feeding a Nexus with the foam filter (you can remove the
foam filter if you want).

I honestly don't think there will be much difference between a bead
filter and a Nexus with an Answer providing you don't exceed the flow
rate. It might be a lot cheaper to put some Kaldness media in your
existing setup and feed it from a bead filter but I've only looked at
the smaller Aquadyne bead filters. Don't forget that with a Nexus you
also need a large air pump.

I think the maintenance of the Nexus system is also a bit more involved
than just backwashing a bead filter since you have to clean the screen
occasionally, it's not just a case of turning a few taps.

--
Regards - Rodney Pont
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