That's not really true. Power filter or UGF, it's still a closed system and
waste products remain in the system until broken down by bacteria and
utilized by the plants or removed through water changes (or wrung-out of
filter pads; is that what you mean?). The question is: where does the waste
remain within the closed system?

In a typical mechanical filtration system, yes, you'll remove some material
on filter pads, but a goodly amount of the waste will still sift into the
substrate and what isn't broken down and used by the root systems or
returned into circulation will incrementally contribute to the eventual and
ultimate deterioration of the aquarium environment. With an undergravel
filtration system, the waste products are broken down within the gravel bed,
pulled through under the plates, and substantially more macro and micro
nutrients are returned into circulation where they are more readily utilized
by the plants (most plants) or removed with water changes.

kush

Chuck Gadd wrote in message
...
On Tue, 03 Dec 2002 23:57:04 GMT, "kush" wrote:

Chuck, what are you on about?

There are going to be nitrogenous waste products in any closed system,
whether you're using mechanical filtration or UGF.

But with a UGF, all of the physical detritus will be pulled into the
substrate. The only way you can remove it is by effective gravel
cleaning. If you don't or can't vacuum the gravel, then all of that
solid waste remains in the water to break down.

In a power filter (or canister, or wet/dry) the solid waste is removed
from the system.


Chuck Gadd
http://www.csd.net/~cgadd/aqua