Underground filters

I have to disagree. With glass bottom tanks, it is very easy to see what is
going on under the UGF. There are no air bubbles. The air stones are located
abotu an inch above the bottom of the lift tubes, so there isn't any way for
air to get under there anyway...
-JD

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

On Oct 9, 7:20?am, "jd" wrote:
Yeah, I can relate with the cleaning of the crud off th e plates, but
I only do that when I'm tearing atank down, which is hardly ever now.
Since I'm not doing commercial or research work any more, my tanks
are all recreational, and I don't have to tear them down unless there
is a good reason. I have tanks that have been going for 6 years
without a teardown, and they're rock solid.....
-JD


- Show quoted text -

As you and RM mentioned...the crud under the plates is my biggest
*con* when it comes to using them.
(Pay no attention JD to the troll tailing me...we are simply
discussing the pros and cons of them and he has to make it into
something it's not...sorry *for* him).
It's that crud that is basically a ticking time bomb. Often an area of
it becomes a toxic cess pool that can release a toxic gas bubble into
the tank.

I'm not big on fluid dynamics, but it seems totally plausible to me that
JD
was holding such a bubble in a static location (a "dead" corner?) under
the
UGF with the flow from his air pump, and the failure of the pump is what
allowed it to diffuse into the tank. THe rapidity with which his water
quality dropped (2 days, IIRC) indicates more than just normal metabolic
action of some fish in a heavily planted tank. JD's story may actually be
another indictment of UG filters, as that rapid drop in water quality
might
not have occurred if the UGF wasn't there, but I guess not enough is known
to say for sure.

DaveZ