Undergravel filters are fine, *if* you have appropriate flow and a decent
filter plate. If you can keep the water flowing, and avoid dead spots, a
good UG will turn your entire gravel bed into a bio filter.

If you have a aspare tank to play with, try this: set it up, with the UG,
but don't turn on the UG (powerhead, air drive, whatever. Leave it off).
Note that you'll have to have the water level below the top of the exhaust
tubes for tghis test.

Get the tanks set up, and throw in a bunch of trash fish (feeders). Watvch
your water chemistry until it stabilizes, then add fish until its saturated
(can't support any more fish). Now, turn on the UG filter, but don't change
anything else. Watch your water chemistry change for the better. Now, try
adding more fish, and see how many more the tank will support now....

Some folks have problems with plants in their tanks with UG filters. I get
around that by only putting UG filters in part of the tank (where plants
won't be).....

Keep in mind that the setup and quality of the UG filter are critical...

--JD



"Tynk" wrote in message
ps.com...

Jen wrote:
"Jen" wrote in message
...
So what's the general consensus on using undergravel filters? Are they
good or bad?


Thanks to all the replies. I'll think when I change over to tropical
I'll
take it out, and see how it goes.

Jen

Jen,
With the types of filters available these days, and ease of care with
them, don't bother with an UGF.
If they're not maintained properly they become cess pools.
With an external power filter, or even a canister, all you need to do
is rinse out the pad in old tank water and replace it inside the filter
housing. By doing this you don't lose any nitrifying bacteria like you
would if you rinsed it under tap water or simply replaced with a new
one. The only time a new one is needed is when the old one has holes
worn in it.
*side note*
Could you please not cross post.
Thank you.