"Gizela" u wrote in
message ...
OK....the filter that came with my aquarium is the undergravel
type....I
have read mixed reviews about these....

Are these OK? Are these as bad as some sites say they are? If not what
is a
good type of filter to get?

HELP

Angela

Undergravel filters (UGF) are excellent biological filters, but poor
mechanical filters and have no chemical filtration capability (carbon,
peat). The best applications for UGFs or RUGFs (UGFs run backwards) are
for low bio-load tanks, or in combination with other filters (which take
care of the mechanical filtration).

The UGF relies on an airpump/airstone or a powerhead. The water
travelling up the riser pipe pulls water through the substrate where you
have millions of hungry bacteria which break down all the waste products.
You usually still need to gravel vacuum periodically as the waste usually
accumulates faster than it can be broken down. This will be true for any
filter and any substrate except sand (if the filters are positioned to
collect the detritus sliding over the sand). hth

If you indicate the tank size and fish population planned, the answers
might be fine-tuned better.

NetMax