"Mark" wrote in message
...

"NetMax" wrote in message
...

"Chris Palma" wrote in message


...

The sense I'm starting to get from the group is that airstones
aren't
all
that popular. I have a few in my 75gal, and like them, but if they
aren't
a good idea I suppose that I could just remove them.

snipped for brevity

Being noisy
for fish is not a frequently discussed topic, as posts tend to
gravitate
around water problems, diseases and compatability.

Indeed they do. :-) Are NetMax and I the only ones worried about our
fish
being physically fit as a fiddle, but mentally they're being driven up
the
wall (or side of fish tank) by the torture of a constant buzzing. I've
seen
the film The Ipcress File - I'd hate to be subjecting my fish to that!

Not at all. This is where to come for information on a complete variety
of fish-husbandry topics. Once something is brought to light, I'm sure
many lurkers go back to their aquarium to 'check it out'. Speaking of
being brought to 'light' another peeve of mine is people who turn on the
tank lights in a dark room. Since fish have no eyelids, the sudden light
is quite a shock. I'm not a fish-hugger (that would be tough to do ;~),
but some common sense can go a long way to making the creatures in our
charge more comfortable.

So, I'm not really worried about the o2 levels, circulation etc. (Ok -
the
truth is: I am - but not for this particular posting!) What I was
interested
in is if there's any scientific evidence for the actual volume levels
and
the effect of the constant buzzing on the fish. From what I'm reading,
the
answer to both questions seems to be "not that we're aware of"? That's
OK -
I'll carry on searching as I'm sure there must be something.

Do post back anything interesting you come across. I just go by
observation, but I have no comparative levels to reference.

The "hot topic", however, seems to be the solution to the problem (if
indeed
there is a problem in the first place). Again, the order of the day
here is
"quiet" as opposed the GPM, o2, circulation etc etc. I think I'm right
in
saying that the consensus is to get an external pump and filter? If so,
any
recommendations on good makes, thinks to look out for and so on?

On canister filters, there isn't (imo) any current models which need to
be avoided because of some horrible defect or characteristic. Pick a
unit which will comfortably take care of your fish-load (though the
filters are sized to tank volume). Check what the unit includes as even
identical models can be packaged differently (you can discover that the
one on sale didn't include shut-off valves, filtration media etc, and
actually comes out more expensive). Watch for running costs for
proprietary filtration media which is replaced periodically. On-line
purchasing & LFS sales/liquidations seem to be the best places/times to
buy, with a marginal increase in risk. Used canisters are much more
risky, as there has historically been a few problems and even today
occasionally a unit has a mis-tolerance on the mating parts of the
casings or a fitting, resulting in some type of leak (much less frequent
today though). Otherwise, everyone can chirp up for their favorite
filter ), but that gets very subjective ;~). Objective credibility
suffers when you only own one filter and it's your favorite, and your
basis for dissing another manufacturer is because you know someone who
didn't like it ;~)

On the point of noise, I think all the canisters are an order of
magnitude quieter than an airstone, so the difference between
manufacturers might be of no significance. It is also difficult to
measure. As example, I currently have in my livingroom an Eheim 2213 and
a Fluval 304 running (about 10 feet away from each other). Standing at a
point between them (and concentrating hard), I hear the Eheim more, but
the Eheim's harder plastic case and/or the construction of the cabinet it
is in, makes the actual noise source, the cabinet. Listening a few
inches from the filters, the Fluval is slightly louder. Listening with
my ear on the tank, the Eheim is louder, but again, there are the
variables of tank dimensions etc, and this assumes that a fish's hearing
range was comparable to my own. Suffice to say, canister acoustics might
be a mute point.

An interesting variable for someone with more time & interest than I
have, is that my Fluval uses a corrogated hose, while my Eheim uses a
smooth hose (originally I wasn't keen on using a corrogated hose as I
thought it would create more resistance, but after using them, I think
the extra turbulence inside, and the fact that they are opaque, keeps
them cleaner far longer). On the topic of noise, a corrogated hose would
(I think) create noise as the water flowed over the ridges, however the
motor noise from the filter would be attenuated by these ridges, so
perhaps the noisier hose gives you a quieter tank?!

ps: In an earlier life, I designed sound suppresion equipment, but I'm
having trouble drawing parallels to underwater applications.
NetMax

Cheers
Mark
snip