midposted..

"bannor" bannor -at- echoes - net - mind the spam block wrote in
message ...
Netmax,

I know you almost swear by these filters... I have one that is about 3
months old... keeps sucking air in somewhere... cycles about a minute
or so apart... gets noisey, then spits out a bunch of air bubbles...
if I rock the filter I can hear them being spit back out again and
after a few minutes of rocking it back and forth the noise stops for a
little while anyway... then the whole process starts again.

A few years ago, the Eheim classics were my favorites, today it's the
Fluvals, because of what I liked in their last round of design changes
(and the amount of time I've logged with them). In a year or two, it
might be someone else, if they can do as good a job (or better) at a
lower price (I'm a bit frugal ;~). My loyalty gets won by design
features & prices, so today, imo Fluval has a great product. I don't
publicize who I work for, so my loyalty can move to whatever I think
presents the best value at any given time, and sometimes it's something
my competitors have and I don't (

I have used silcone lubricant on the only "O"ring that came with the
filter but I actually think the air is coming in from elsewhere. More
than I can account for by ingestion from the intake. I do have lots
of very very tiny bubbles generated by a bio-wheel Hot Magnum Pro
filter on the same tank but these bubbles are very tiny and I seldom
see them actually making the trip to the far side of the aquarium
where the intake for the 404 is.

I don't think the airstones are a problem. I had an overstocked
Angelfish tank which I needed to increase the oxygenation, so I added an
airstone under the intake of a Fluval 304 (or 404, I can't recall the
model, it's been a while since I serviced it). The filter sucks the
airbubbles in and shoots them out, vastly increasing the oxygenation and
breaks up the surface protein layer. I haven't noticed any change in the
filter's noise or operating efficiency. I was actually surprised that it
seemed to make so little difference to the filter, as older versions of
canisters would suffer badly from operating this way. Air entrapment
used to be a big problem. I don't recommend you intentionally do this,
but you should be aware that it can be done with no apparent
consequences.

IE: intake for 404 is in far left back corner of 4 ft tank, bio-wheel
is about 3 horizontal feet away and 18 inches up on the back wall.
(actually on the top rim, but I am subtracting the gravel layer from
the total height of the tank. The output of the 404 is actually
behind the bio-wheel output, which is a waterfall type output that has
plastic extending about 1.5 inches below water level, so the 404
output nozel rests completely behind this 'plastic' wall and is
directed to the right hand corner... thus giving me fairly good round
the tank circulation.

The tank is very highly oxygenated... 3 airstones... so there are
those small bubbles floating around, just not very many by the intake
of the 404...

shoot... I don't think I can describe it any better... the top locks
down like it is supposed to... could it be the little hand-pump primer
on the 404? That doesn't seem to have any sort of tight fitting "O"
ring around the plunger, could the air be coming in there?

Obviously, I can't test it with soapy water since that would cause the
soap to be ingested into the filter.
Any suggestions?

Everything upstream of the impeller is negative charged, so that would be
the area of interest. Everything after the impeller would be positively
charged, so any leak would manifest itself by weeping water. My guess
would be that the adapter which the hoses connect to, might be the
culprit. Check where the adapter connects to the motor head. Perhaps
one of the two gaskets has been damaged or is missing, or some foreign
material is across where the gasket sits. A drop of methylene blue in
that area might show the problem, but I'm guessing as I've never
encountered this situation before.

At my store, I don't carry replacement parts for the new Fluvals (it
hasn't been a necessity, knock on wood), but when the need arises, I just
take the parts I need off of a new filter from the shelf. I then order
the parts needed (1 week turn-around) and replace them so the filter can
be sold again. The biggest problem with all the filter brands is missing
parts, rather than defective parts. If your filter is new, then see if
your LFS can do the same thing. A filter is not something you want to be
without while waiting for parts. You can also try swapping only your
adapter module, but from a manufacturing perspective (I was a
manufacturing engineer in a previous life ;~), the tolerances are harder
to control on a larger plastic assembly, than on the smaller adapter, so
if no obvious problem is seen, then an out-of-round condition would more
likely be in the motor head where the adapter module snaps in.

It might vary by district, but where I am, Hagen (& Marineland) reps are
very good about replacing components. They don't even ask me for sales
receipts *shhhh* ;~). We are doing them a favour, protecting their
reputation by quickly fixing any problems which arise, so they are more
than happy about replacing the parts we used. If your LFS doesn't solve
your problem, go elsewhere and/or contact the rep directly. My advice is
the same for any manufacturer. Aquarium products (especially filters)
are critical components keeping your livestock alive. Don't settle for
defective operation from anyone. Let me know how it turns out.

NetMax