"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. I recently buried
all of them under polished river stones to slow down the flow a bit, do
you think that makes any noticeable difference to the noise level in
the
tank?

All these components have their pros & cons, and airstones might be noise
generators. Put your ear to the tank and listen to the difference
between off and on. If your pump is quiet and/or the tank is large, then
there might be little difference. There are many benefits to airstones,
so I wouldn't want to discourage their use without pointing out pros &
cons. They do boost the O2 level, though it's less than originally
thought. The help with circulation, especially in areas which might be
hard to reach with an outside filter. They break up the surface protein
layer and help re-oxygenation at the surface. They can be almost
essential in high fish-load tanks. The biggest drawback to them is that
somewhere you need an airpump, which can be noisy for you. Being noisy
for fish is not a frequently discussed topic, as posts tend to gravitate
around water problems, diseases and compatability.

I know this is a huge can of worms I'm opening, but the other "sense of
the group" I get is that most people think that canister filters are
much
better than hang on the back power filters, like the AquaClear I use.
Is
there a simple reason why canisters are so superior?

Again, all these components have their pros & cons. It's not about
canister vs powerfilter, as there are many filter technologies like FBs,
UGFs, RUGFs, wet/dry etc. Generally, the greater the surface area of
filtration media, the less servicing you need to do. The further the
filter is away from the tank, the more flexibility you will have (tank
right against the wall, hoses direct flow, motor noise can be isolated
etc). The bigger (or more compartmented) the filter is, the more options
you have for massaging the water parameters. The slower the flow rate,
the better the biological & chemical filtration.

Is a canister filter better than a powerfilter (Penquin, AquaClear etc)?
In most applications, yes, especially in efficiency, but - it depends on
how you define 'which is better'. The canister is more expensive and it
provides features or capabilities which you may not need. Most people
with multiple tanks have an arsenal of filters, including both types. If
you were to compare the value of a powerfilter to a canister, (and by
value, I'm taking the (extra efficiency + features you will use) and
dividing by the purchase cost), then the best value would be (imo), an
AquaClear filter. As soon as you need a feature provided by a canister
(ie: another compartment for sintered glass, putting the tank flat
against the wall, longer servicing interval etc), then you swallow hard,
pay more money and know that the overall efficiency will be better which
is good for you and for the fish. If you don't need a feature not
provided by your powerfilter, and your tank is well balanced, not
underfiltered, your maintenance routine is long established, then why
would you change?

All this talk about filters, remember, it's mostly all opinions ;~)
NetMax

--chris
snip