> Having arrived after the event as far as the filtration discussion is
> concerned it seems to me that all methods have something to offer in water
> quality control depending on the experience and confidence of the user.
>
> I agree with Craig that plants are the most natural, most aesthetically
> pleasing, most likely to make your fish look good,
"high five" on that one. Plants are good. Rainbowfish are beautiful
fish. One need only see the incredible transformation from a pale
rainbowfish cowering in a bare dealer's tank to the glorious, radiant
display that they put on in a planted tank to be convinced of that
statement.
> but even plants need
> water changes. You only have to watch them after a water change to see the
> bubbles flying to the surface when nothing else has changed.
That probably means that the plants have become limited by some nutrient
that has been depleted, rather than being inhibited by metabolites. A
surprising number of planted tanks are limited by potassium.
Don't get me wrong... water exchanges are a wonderful idea, provided you
are using good quality water for the exchange.
> Aside from the mechanical filtration aspect for water clarity ( so we can
> see our pretty fishies) all other aspects of filtration are really water
> quality modification and are changing one metabolite for another (perhaps
> less toxic to one or other of the tank inhabitants) so there is still a
> build up of metabolites unless water changes are performed regularly.
Activated carbon is more or less an exception to that statement. Organic
molecules are adsorbed, and (more or less) water molecules are
"exchanged" in the process.
Craig