Under Gravel filters

[Glengoyne]

I'm fairly new, well returning actually, to this hobby. My family has
a couple of small 10 gal tanks that we are currently tending. We're
planning on stepping that up considerably to a seventy gallon or
possibly a 110 gallon that a friend of mine is possibly looking to part
with.

When I said I was returning to the hobby, back when I was in High
School and some of my college years I kept a 55 gallon African Cichlid
tank. That tank had only artificial plants, an under gravel filter
system(air driven, not powerheads). I did a 20/25 percent water change
every other week, cleaning the gravel as I did the water change. I
supplemented this with a Diatom filter, just about every six weeks.
Now some twenty years later, I'm told I was doing it all wrong. The
catch is that I was very successful with the Africans, I even had luck
raising a few broods of young.

In any case, I'm looking at setting up a new large aquarium, and am
wondering why not an undergravel system as opposed to the considerably
more expensive alternatives. Or even why not a UG system to compliment
a canister filter? The UG filters seem to carry the added bonus that
they are lower maintenance. I mean, you have regularly clean the
gravel anyway, don't you?

I'm asking because they (UG filters) seem to be out of vogue, when I
remember them working quite well.

For the large tank, I'm considering a UG filter setup with a
couple...or more...powerheads driving the system. The power heads will
have the added benefit of stirring up the surface of the water to
assist in oxegenation(sp?) of the water. I will definately be
employing a Diatom occasionally, as it really did an impressive job
back in the day. Even if it was just essentially polishing the water.
Please let me know if I'm nuts.

[Rod Bacon]

There's a huge debate about UGF's on the 'net. Google around a bit, and
you'll find a lot of opinions out there. I just setup a 200 litre tank,
and went with a RUGF (reverse undergravel) fed by two internal power
filters (you need to pre-filter the water before using an RUGF).

The main reason I did this was to benefit from the large surface area
the substrate offers for bacterial growth, instead of just having the
gravel sitting there doing nothing. I think running the UG in reverse
makes more sense, as it helps to avoid dead spots caused by ornaments,
etc. and also prevents "packing" of the gravel.

My tank is only 3 weeks old, and I've just entered phase 2 of my cycle
(Ammonia to zero, Nitrate off the scale).

So far, it seems like it's doing a great job, although I've only got
1/2 dozen fish at the moment. My plants are even growing!

[Glengoyne]

So you filter the water with the "internal power filters", and then
force the filtered water down through the UnderGravel system where it
percolates up through the gravel. Interesting approach. I'll be
Googling RUGF as well, to see more specifics as well as get more info
on the approach I've been considering.

[Justin Boucher]

No, you're not nuts.
I have been very successful and running healthy tanks with a UGF powered by
powerheads rather than the typical air stones. I even had a healthy growth
of live plants that needed regular trimming. All this in a 100USG and 40USG
tanks.

I found that using enough water flow from the powerheads so that
theoretically the tank gets turned over every 10 minutes. For example, in
the 100 gal tank, I had two powerheads at 300gph each. My tanks remained
really clear and the fish didn't mind the flow rate.

Justin

"Glengoyne" > wrote in message
oups.com...
> I'm fairly new, well returning actually, to this hobby. My family has
> a couple of small 10 gal tanks that we are currently tending. We're
> planning on stepping that up considerably to a seventy gallon or
> possibly a 110 gallon that a friend of mine is possibly looking to part
> with.
>
> When I said I was returning to the hobby, back when I was in High
> School and some of my college years I kept a 55 gallon African Cichlid
> tank. That tank had only artificial plants, an under gravel filter
> system(air driven, not powerheads). I did a 20/25 percent water change
> every other week, cleaning the gravel as I did the water change. I
> supplemented this with a Diatom filter, just about every six weeks.
> Now some twenty years later, I'm told I was doing it all wrong. The
> catch is that I was very successful with the Africans, I even had luck
> raising a few broods of young.
>
> In any case, I'm looking at setting up a new large aquarium, and am
> wondering why not an undergravel system as opposed to the considerably
> more expensive alternatives. Or even why not a UG system to compliment
> a canister filter? The UG filters seem to carry the added bonus that
> they are lower maintenance. I mean, you have regularly clean the
> gravel anyway, don't you?
>
> I'm asking because they (UG filters) seem to be out of vogue, when I
> remember them working quite well.
>
> For the large tank, I'm considering a UG filter setup with a
> couple...or more...powerheads driving the system. The power heads will
> have the added benefit of stirring up the surface of the water to
> assist in oxegenation(sp?) of the water. I will definately be
> employing a Diatom occasionally, as it really did an impressive job
> back in the day. Even if it was just essentially polishing the water.
> Please let me know if I'm nuts.
>

[Justin Boucher]

No, you're not nuts.
I have been very successful and running healthy tanks with a UGF powered by
powerheads rather than the typical air stones. I even had a healthy growth
of live plants that needed regular trimming. All this in a 100USG and 40USG
tanks.

I found that using enough water flow from the powerheads so that
theoretically the tank gets turned over every 10 minutes. For example, in
the 100 gal tank, I had two powerheads at 300gph each. My tanks remained
really clear and the fish didn't mind the flow rate.

Justin

"Glengoyne" > wrote in message
oups.com...
> I'm fairly new, well returning actually, to this hobby. My family has
> a couple of small 10 gal tanks that we are currently tending. We're
> planning on stepping that up considerably to a seventy gallon or
> possibly a 110 gallon that a friend of mine is possibly looking to part
> with.
>
> When I said I was returning to the hobby, back when I was in High
> School and some of my college years I kept a 55 gallon African Cichlid
> tank. That tank had only artificial plants, an under gravel filter
> system(air driven, not powerheads). I did a 20/25 percent water change
> every other week, cleaning the gravel as I did the water change. I
> supplemented this with a Diatom filter, just about every six weeks.
> Now some twenty years later, I'm told I was doing it all wrong. The
> catch is that I was very successful with the Africans, I even had luck
> raising a few broods of young.
>
> In any case, I'm looking at setting up a new large aquarium, and am
> wondering why not an undergravel system as opposed to the considerably
> more expensive alternatives. Or even why not a UG system to compliment
> a canister filter? The UG filters seem to carry the added bonus that
> they are lower maintenance. I mean, you have regularly clean the
> gravel anyway, don't you?
>
> I'm asking because they (UG filters) seem to be out of vogue, when I
> remember them working quite well.
>
> For the large tank, I'm considering a UG filter setup with a
> couple...or more...powerheads driving the system. The power heads will
> have the added benefit of stirring up the surface of the water to
> assist in oxegenation(sp?) of the water. I will definately be
> employing a Diatom occasionally, as it really did an impressive job
> back in the day. Even if it was just essentially polishing the water.
> Please let me know if I'm nuts.
>

[Eric]

On Mon, 5 Sep 2005 00:25:11 -0500, Rod Bacon wrote
(in article om>):

> There's a huge debate about UGF's on the 'net. Google around a bit, and
> you'll find a lot of opinions out there. I just setup a 200 litre tank,
> and went with a RUGF (reverse undergravel) fed by two internal power
> filters (you need to pre-filter the water before using an RUGF).

Marineland makes a submersible powerhead sponge filter with a reverse
undergravel attachment. I know a guy who uses them in his turtle tank. The
water passes through the sponge before it gets pumped into what would
normally be the lift tube of the UGF

In general I think UGF is cool.

-E

[lgb]

In article om>,
says...
> There's a huge debate about UGF's on the 'net. Google around a bit, and
> you'll find a lot of opinions out there. I just setup a 200 litre tank,
> and went with a RUGF (reverse undergravel) fed by two internal power
> filters (you need to pre-filter the water before using an RUGF).
>
One of the points in contention is the use of UGF/RUGF with live plants.

And the need to eventually tear down the whole tank to clean it.

I read a lot of the stuff on them but since I have a heavily planted
tank, I went with an Aquaclear power filter. Works great, easy to
clean, and inexpensive.

--
BNSF = Build Now, Seep Forever

[Elaine T]

Glengoyne wrote:
> I'm fairly new, well returning actually, to this hobby. My family has
> a couple of small 10 gal tanks that we are currently tending. We're
> planning on stepping that up considerably to a seventy gallon or
> possibly a 110 gallon that a friend of mine is possibly looking to part
> with.
>
> When I said I was returning to the hobby, back when I was in High
> School and some of my college years I kept a 55 gallon African Cichlid
> tank. That tank had only artificial plants, an under gravel filter
> system(air driven, not powerheads). I did a 20/25 percent water change
> every other week, cleaning the gravel as I did the water change. I
> supplemented this with a Diatom filter, just about every six weeks.
> Now some twenty years later, I'm told I was doing it all wrong. The
> catch is that I was very successful with the Africans, I even had luck
> raising a few broods of young.
>
> In any case, I'm looking at setting up a new large aquarium, and am
> wondering why not an undergravel system as opposed to the considerably
> more expensive alternatives. Or even why not a UG system to compliment
> a canister filter? The UG filters seem to carry the added bonus that
> they are lower maintenance. I mean, you have regularly clean the
> gravel anyway, don't you?
>
> I'm asking because they (UG filters) seem to be out of vogue, when I
> remember them working quite well.
>
> For the large tank, I'm considering a UG filter setup with a
> couple...or more...powerheads driving the system. The power heads will
> have the added benefit of stirring up the surface of the water to
> assist in oxegenation(sp?) of the water. I will definately be
> employing a Diatom occasionally, as it really did an impressive job
> back in the day. Even if it was just essentially polishing the water.
> Please let me know if I'm nuts.

Everyone else has pretty much answered your question. I agree that
reverse flow is superior to forward because you don't collect much mulm
under the filter plates. The one trick I wanted to add concerns the
fish digging. When your cichlids inevitably dig down to the UGF plate,
water will flow where there is no gravel and you will lose much of the
filtration. Cut a piece of flourescent lighting diffuser ("egg crate")
to fit on top of the UGF. Put the plate down, then the lighting
diffuser, and then the gravel. Fish can only dig down to the diffuser
so you will always have some gravel over all areas of the plate.

--
Elaine T __
http://eethomp.com/fish.html <'__><
rec.aquaria.* FAQ http://faq.thekrib.com

[NetMax]

"Elaine T" > wrote in message
. ..
> Glengoyne wrote:
>> I'm fairly new, well returning actually, to this hobby. My family
>> has
>> a couple of small 10 gal tanks that we are currently tending. We're
>> planning on stepping that up considerably to a seventy gallon or
>> possibly a 110 gallon that a friend of mine is possibly looking to
>> part
>> with.
>>
>> When I said I was returning to the hobby, back when I was in High
>> School and some of my college years I kept a 55 gallon African Cichlid
>> tank. That tank had only artificial plants, an under gravel filter
>> system(air driven, not powerheads). I did a 20/25 percent water
>> change
>> every other week, cleaning the gravel as I did the water change. I
>> supplemented this with a Diatom filter, just about every six weeks.
>> Now some twenty years later, I'm told I was doing it all wrong. The
>> catch is that I was very successful with the Africans, I even had luck
>> raising a few broods of young.
>>
>> In any case, I'm looking at setting up a new large aquarium, and am
>> wondering why not an undergravel system as opposed to the considerably
>> more expensive alternatives. Or even why not a UG system to
>> compliment
>> a canister filter? The UG filters seem to carry the added bonus that
>> they are lower maintenance. I mean, you have regularly clean the
>> gravel anyway, don't you?
>>
>> I'm asking because they (UG filters) seem to be out of vogue, when I
>> remember them working quite well.
>>
>> For the large tank, I'm considering a UG filter setup with a
>> couple...or more...powerheads driving the system. The power heads
>> will
>> have the added benefit of stirring up the surface of the water to
>> assist in oxegenation(sp?) of the water. I will definately be
>> employing a Diatom occasionally, as it really did an impressive job
>> back in the day. Even if it was just essentially polishing the water.
>> Please let me know if I'm nuts.
>
> Everyone else has pretty much answered your question. I agree that
> reverse flow is superior to forward because you don't collect much mulm
> under the filter plates. The one trick I wanted to add concerns the
> fish digging. When your cichlids inevitably dig down to the UGF plate,
> water will flow where there is no gravel and you will lose much of the
> filtration. Cut a piece of flourescent lighting diffuser ("egg crate")
> to fit on top of the UGF. Put the plate down, then the lighting
> diffuser, and then the gravel. Fish can only dig down to the diffuser
> so you will always have some gravel over all areas of the plate.
>
> --
> Elaine T

On a large tank using two or more UGF plates, you could have some plates
running as UGFs and then connect the output of the powerhead(s) to the
remaining plates to run them as RUGF. One way would be to run the plates
along the front as RUGF (area where you will be gravel-vacuuming and
where most of the detritus collects), and the rear as UGF (where you have
natural plants feeding off the detritus).

Alternately, the rear as RUGF (where you can't reach to gravel vacuum as
well) and the front as UGF (which gets efficiently vacuumed).

To make amends for possibly confusing Glengoyne, here is an article on
the stuff which has changed in the last 30 years.
http://www.2cah.com/netmax/basics/changes/changes.shtml
You might find it useful (RUGF is the first item of the 16 listed).
--
www.NetMax.tk

[coolchinchilla]

Glengoyne wrote:
<snip>

> I'm asking because they (UG filters) seem to be out of vogue, when I
> remember them working quite well.

I posed this question in a different forum. The major objection to
UGFs is the mulm that inevitably builds up under the plates adds to
the nitrate load in the tank. In essence, USFs are nitrate factories.

At the same time power filters have become quite efficient, so
people prefer them over the work of a UGF.

HTH.
coolchinchilla

[Glengoyne]

I'm still curious about this. When using the gravel vac, does that
remove some of the "mulm" from beneath the tank?


The rest of this isn't directed at you or anyone else
CoolChinnhilla...After Googling as suggested above, I'm a bit confused.
Most of the negative comments seemed to be related to maintenance and
based almost solely on anecdotal evidence.

Among the negative comments...

The gravel gets full of detrius and clogs the plates blocking water
flow to certain locations under the filter. My question to this
is...Well aren't you supposed to vaccuum the gravel anyway? If you
keep your gravel clean, shouldn't that prevent this from occuring?

Either dirty gravel or ornaments create areas where the water simply
doesn't flow through the gravel to the filter below...this causes
"dead" areas where detrimental anaerobic bacteria will build up and
spoil the environment. ...A couple of points actually. First, if
there are "dead" areas in aquariums using UGFs, then why aren't there
"dead" areas in the gravel of other aquariums? Also if I
misunderstood, and the "dead" areas are beneath the gravel under the
filter plates...I actually would think that a UGF pumping 100 plus
gallons of water through itself each hour would account for quite a bit
of flow.

Then a question about RUGF. Is the principle essentially to move water
through the gravel oxygenating it and forcing some of the detrius up
toward the top of the gravel where a canister can deal with it?

[bassett]

Simply take the return tube out and stick your vacuum syphon over the
pipe socket, When the thing runs clean, replace the return tube, You might
need to do it twice a year.

bassett

"lgb" > wrote in message
...
> In article om>,
> says...
>> There's a huge debate about UGF's on the 'net. Google around a bit, and
>> you'll find a lot of opinions out there. I just setup a 200 litre tank,
>> and went with a RUGF (reverse undergravel) fed by two internal power
>> filters (you need to pre-filter the water before using an RUGF).
>>
> One of the points in contention is the use of UGF/RUGF with live plants.
>
> And the need to eventually tear down the whole tank to clean it.
>
> I read a lot of the stuff on them but since I have a heavily planted
> tank, I went with an Aquaclear power filter. Works great, easy to
> clean, and inexpensive.
>
> --
> BNSF = Build Now, Seep Forever

[lgb]

In article >,
says...
> I posed this question in a different forum. The major objection to
> UGFs is the mulm that inevitably builds up under the plates adds to
> the nitrate load in the tank. In essence, USFs are nitrate factories.
>
Interestingly, there are several species that, according to Baensch,
prefer a bottom with mulm on it. Of course, mulm buried under the
gravel doesn't do much for them :-).

--
BNSF = Build Now, Seep Forever

[Rod Bacon]

I have almost completed my cycle in my new 200L tank (with RUGF). Now
my ammonia is 0, and nitrites off the chart, so I'm doing a 15% water
change about every other day to keep things healthy until the nitrates
kick in, and the nitrites disappear (then off to the LFS for some more
interesting varieties!).

When doing the last 2 changes, I vacuumed the gravel bed. Normally I
wouldn't recommend doing it so frequently with a (R)UGF, and generally
wouldn't vacuum the entire bed in one go, becuase of the disruption to
the beneficial bacteria colony in the gravel. I also make it a point to
never vacuum and clean the sponge prefilters at the same time, for the
same bacteria-preserving reasons.

In this case, the first vacuuming revealed a heap of fine green/brown
material in the gravel. I wasn't sure whether this was dirt or
bacteria, or a mixture of both. The second vacuuming, only 2 days
later, revealed similar quantities of the same stuff in the same
locations.

I only have 10 small fish in the tank, and feed them very sparingly. I
also have about a dozen plants, that are all doing very well, with new
growth on most of them. Water is crystal clear, chemistry is good (for
a cycling tank) and all the inhabitents look extrememly happy (damned
Danios sure are playful!).

Given my tank conditions, and the fact that this green/brown stuff came
back so quickly I suspect that the green/brown stuff may indeed be more
(beneficial) bacteria than dirt. Is this what the good bacteria looks
like in large quantities?

If so, I'm also assuming that it's a good thing for the substrate to
re-colonize itself so quickly after a vacuuming.

An comments?

[Charles]

On 5 Sep 2005 22:08:03 -0700, "Glengoyne" > wrote:

>I'm still curious about this. When using the gravel vac, does that
>remove some of the "mulm" from beneath the tank?
>
>
>The rest of this isn't directed at you or anyone else
>CoolChinnhilla...After Googling as suggested above, I'm a bit confused.
> Most of the negative comments seemed to be related to maintenance and
>based almost solely on anecdotal evidence.
>
>Among the negative comments...
>
>The gravel gets full of detrius and clogs the plates blocking water
>flow to certain locations under the filter. My question to this
>is...Well aren't you supposed to vaccuum the gravel anyway? If you
>keep your gravel clean, shouldn't that prevent this from occuring?
>
>Either dirty gravel or ornaments create areas where the water simply
>doesn't flow through the gravel to the filter below...this causes
>"dead" areas where detrimental anaerobic bacteria will build up and
>spoil the environment. ...A couple of points actually. First, if
>there are "dead" areas in aquariums using UGFs, then why aren't there
>"dead" areas in the gravel of other aquariums? Also if I
>misunderstood, and the "dead" areas are beneath the gravel under the
>filter plates...I actually would think that a UGF pumping 100 plus
>gallons of water through itself each hour would account for quite a bit
>of flow.
>
>Then a question about RUGF. Is the principle essentially to move water
>through the gravel oxygenating it and forcing some of the detrius up
>toward the top of the gravel where a canister can deal with it?


Just one comment on the RUGF. the ones I use, Penguin 660R, have a
sponge to protect the intake to the pump. that sponge accumulates
lots of junk, thus the additional canister is not needed, in my
opinion.

[coolchinchilla]

Glengoyne wrote:
> I'm still curious about this. When using the gravel vac, does that
> remove some of the "mulm" from beneath the tank?

When just vacumming the gravel I don't think there's a strong enough
suction to get *under* the plates.

>
>
> Most of the negative comments seemed to be related to maintenance

Yes, I'd say maintenance is the biggest issue I've heard -- that
plus the mulm under the plates.

> The gravel gets full of detrius and clogs the plates blocking water
> flow to certain locations under the filter. My question to this
> is...Well aren't you supposed to vaccuum the gravel anyway? If you
> keep your gravel clean, shouldn't that prevent this from occuring?

If you vacuum all the gravel throughly, then probably not a problem.
I had rockwork in the tank that I didn't tear down every water change.

>
> First, if
> there are "dead" areas in aquariums using UGFs, then why aren't there
> "dead" areas in the gravel of other aquariums?

Gravel by itself doesn't have water flowing through it. The "dead"
areas in a UGF refer to spots under the plates that don't get the
proper flow and then anaerobic (bad) bacteria develop there. You
can quickly create dead areas by fish exposing the plate. Then all
the water starts to go through that exposed part because it offers
the least resistence. That leaves corners without decent flow and
you get anaerobic bacteria. The strength of the powerhead doesn't
make any difference if the plate is exposed somewhere.

HTH.
coolchinchilla

[Rod Bacon]

This is exactly the point the the original poster was trying to make.
If water flow is restricted in an area (or resistence is lowered
elsewhere, as you have suggested) then anaerobic bacteria can
supposedly flourish there... right?

How is this different to a tank with no UGF at all, given that the
whole gravel area is "dead" in such a tank?

[Derek W. Benson]

On 6 Sep 2005 19:32:42 -0700, "Rod Bacon" > wrote:

>This is exactly the point the the original poster was trying to make.
>If water flow is restricted in an area (or resistence is lowered
>elsewhere, as you have suggested) then anaerobic bacteria can
>supposedly flourish there... right?
>
>How is this different to a tank with no UGF at all, given that the
>whole gravel area is "dead" in such a tank?

IMO a tank with no UGF is 10 or 500 times more at risk from these dead
areas forming in the gravel than a tank with a UGF. So why everyone on
planet Earth is always bringing up this argument against the UGF, as
if it is a legitimate argument against its use, is beyond me. I'm
talking about In Comparison To No UGF, just the gravel laying there
with a cannister filter on the tank. With the no-UGF tank, what you do
is vacuum the gravel, the gravel is sucked up and falls back down,
together with new water which is filled with oxygen. So you're keeping
the gravel bed oxygenated by stirring up the gravel all the way to the
bottom. In this no-UGF tank if you don't vacuum or otherwise stir up
the gravel it will after a while be depleted of oxygen, the aerobic
bacteria will die off, anaerobic bacteria will start growing and
producing all their vile by-products.

The UGF sucks water filled with oxygen through the gravel all the time
and keeps your gravel bed oxygenated. As a practical matter, with for
example digging cichlids, if there's a spot of the gravel removed and
the filter plate is open, all one has to do is stick one's hand in the
tank and cover back up the open spot. No disaster is going to happen
if there's an open spot for 8 or 9 hours while you're at work, you
come home and discover what your naughty fish have been doing while
you're away; just cover the filter plate with the gravel that the fish
have moved. This UGF gravel bed should also be vacuumed as standard
procedure when changing water.

-Derek

[lgb]

In article >,
says...
> This UGF gravel bed should also be vacuumed as standard
> procedure when changing water.
>

OK, now tell me how you vacuum the gravel in a heavily planted tank :-).

--
BNSF = Build Now, Seep Forever

[Glengoyne]

That was the point I was trying to make. If a tank with a UGF is
susceptible to "dead" spots fostering detrimental anaerobic bacteria,
then how much moreso is a regular tank without any flow of oxygenated
water through any of the gravel?

back on the RUGF. What is the objective? It doesn't seem that the
plan is to clean the tank by pushing water up through the gravel. In
both scenarios I've seen, either a canister filter or a "sponge" filter
is used to feed the RUGF. So both are supplying filtered water to the
ugf system. About the only thing I can see is that it might suspend
more debris in the water, and thereby promote better canister or power
filter performance.

[Derek W. Benson]

On Wed, 7 Sep 2005 15:11:42 -0700, lgb > wrote:

>In article >,
says...
>> This UGF gravel bed should also be vacuumed as standard
>> procedure when changing water.
>>
>
>OK, now tell me how you vacuum the gravel in a heavily planted tank :-).

My main tank really isn't heavily planted, but what I do is vacuum as
close to each of the plants as I can and don't worry about the areas
directly beneath each plant. I think people have posted about this
before, and what they've said is that the plant roots are creating
biological activity wherever they reach, or the roots are releasing
CO2 or oxygen or whatever. So the gravel areas where plant roots are
growing don't go anaerobic because of this activity.

-Derek

[Elaine T]

Glengoyne wrote:
> That was the point I was trying to make. If a tank with a UGF is
> susceptible to "dead" spots fostering detrimental anaerobic bacteria,
> then how much moreso is a regular tank without any flow of oxygenated
> water through any of the gravel?
>
> back on the RUGF. What is the objective? It doesn't seem that the
> plan is to clean the tank by pushing water up through the gravel. In
> both scenarios I've seen, either a canister filter or a "sponge" filter
> is used to feed the RUGF. So both are supplying filtered water to the
> ugf system. About the only thing I can see is that it might suspend
> more debris in the water, and thereby promote better canister or power
> filter performance.
>
It's fairly simple. Go anywhere there is an airlift UGF tank that's
been running for more than six months and look under the filter plates
from the bottom of the tank with a flashlight. You will find rotting
debris that will eventually build up to the extent that the tank must be
broken down to avoid high nitrates and pH crash.

RUGF prefilters the water going under the plates so that far less debris
builds up under the filter plates. This results in far more stable tank
setup.

The overall point of UGF or RUGF is to use the gravel bed as a large
biofilter. In freshwater using modern filters this is pretty much
unnecessary, but you seemed pretty set on some form of UGF in your
original posts.

--
Elaine T __
http://eethomp.com/fish.html <'__><
rec.aquaria.* FAQ http://faq.thekrib.com

[lgb]

In article >,
says...
> I think people have posted about this
> before, and what they've said is that the plant roots are creating
> biological activity wherever they reach, or the roots are releasing
> CO2 or oxygen or whatever. So the gravel areas where plant roots are
> growing don't go anaerobic because of this activity.
>
That takes care of my whole tank :-).

--
BNSF = Build Now, Seep Forever

[NetMax]

"coolchinchilla" > wrote in message
...
> Glengoyne wrote:
>> I'm still curious about this. When using the gravel vac, does that
>> remove some of the "mulm" from beneath the tank?
>
> When just vacumming the gravel I don't think there's a strong enough
> suction to get *under* the plates.
>
>>
>>
>> Most of the negative comments seemed to be related to maintenance
>
> Yes, I'd say maintenance is the biggest issue I've heard -- that plus
> the mulm under the plates.
>
>> The gravel gets full of detrius and clogs the plates blocking water
>> flow to certain locations under the filter. My question to this
>> is...Well aren't you supposed to vaccuum the gravel anyway? If you
>> keep your gravel clean, shouldn't that prevent this from occuring?
>
> If you vacuum all the gravel throughly, then probably not a problem. I
> had rockwork in the tank that I didn't tear down every water change.
>
>>
>> First, if
>> there are "dead" areas in aquariums using UGFs, then why aren't there
>> "dead" areas in the gravel of other aquariums?
>
> Gravel by itself doesn't have water flowing through it. The "dead"
> areas in a UGF refer to spots under the plates that don't get the
> proper flow and then anaerobic (bad) bacteria develop there. You can
> quickly create dead areas by fish exposing the plate. Then all the
> water starts to go through that exposed part because it offers the
> least resistence. That leaves corners without decent flow and you get
> anaerobic bacteria. The strength of the powerhead doesn't make any
> difference if the plate is exposed somewhere.

My understanding is that the water does flow through the gravel,
re-oxygenating the aerobic bacteria which coat the gravel.

A dead spot is under ornaments and stones. The UGF pulls detritus
inwards, and the path of least resistance can become the edges of large
stones, but then the detritus collects (under something it will be less
likely to be gravel-vaccumed), and without a flow of water, the bacteria
developed are anerobic. A little anaerobic bacteria is of little
consequence. Some filter systems even encourage it, but pockets of
anerobic activity produce nasty gases which can be very toxic to fish
when the stone is picked up. This is especially bad under the slate used
with driftwood.

Pros/cons of operating with or without a UGF ironically come down mostly
to the mechanical filtration, not biological. Without a UGF, but with
good mechanical filtration, the detritus has a better chance of being
brought out of the tank into a filter media which gets cleaned
periodically. With a UGF, it collects in the gravel and convert to
dissolved organic compounds (DOCs). The RUGF operates identically, but
due to the reversed current, the detritus does not settle so deeply,
theoretically making it easier to gravel-vacuum. The key with any system
is to remove rotting organic matter at a fast enough rate so that it
doesn't accumulate and pollute the water. Water changes are also part of
the routine, diluting the effects.
--
www.NetMax.tk

> HTH.
> coolchinchilla

[coolchinchilla]

For the what-it's-worth department on UGFs...

Today I tore down my 30 gallon tank with a UGF because I want sand
for a substrate. The tank had been running with a UGF and a
powerhead for 3 months. I did 25%-30% water changes about every
week -- at least every 10 days with deep gravel vacs.

I was AMAZED at the amount of mulm under the plates in that short of
time. I tried someone's suggestion to put the gravel vac over the
stand pipe which stood 3 inches above the plates. It took out some
of the gunk, but nothing like what was left.

coolchinchilla

[Derek W. Benson]

On Fri, 09 Sep 2005 17:36:31 GMT, Elaine T >
wrote:

>It's fairly simple. Go anywhere there is an airlift UGF tank that's
>been running for more than six months and look under the filter plates
>from the bottom of the tank with a flashlight. You will find rotting
>debris that will eventually build up to the extent that the tank must be
>broken down to avoid high nitrates and pH crash.

I've always found it fairly simple to remove most, if not all, of this
brown silt from under the plates on a Ugf. I'd take that 1/4 inch
tubing which is used with a pump and airstone and stick it down the
riser tube and under the plate and suck on it and siphon out the brown
silt.

The only stuff I've ever found under a Ugf filter plate is this very
fine brown silt, like brown mud but extremely fine small particles.
You're sure this stuff is debris which is still rotting? I've always
considered this silt to be a leftover by-product of the rotting
process; the bacteria have finished with it so it's not rotting
anymore, inert matter that the bacteria are done with. I've never read
any research or studied this brown silt myself so I don't know, this
is just the way I've always thought about it.

-Derek

[lgb]

In article >,
says...
> The key with any system
> is to remove rotting organic matter at a fast enough rate so that it
> doesn't accumulate and pollute the water. Water changes are also part of
> the routine, diluting the effects.
>
OK, I'm confused. What's the difference between "rotting organic
matter" and mulm?

--
BNSF = Build Now, Seep Forever

[NetMax]

"lgb" > wrote in message
...
> In article >,
> says...
>> The key with any system
>> is to remove rotting organic matter at a fast enough rate so that it
>> doesn't accumulate and pollute the water. Water changes are also part
>> of
>> the routine, diluting the effects.
>>
> OK, I'm confused. What's the difference between "rotting organic
> matter" and mulm?
>
> --
> BNSF = Build Now, Seep Forever

This is somewhat subjective, but:

Detritus is what falls into the gravel. This is a wide collection of
organic matter, such as feces, scales and uneaten foods.

After some time, it bunches up and begins breaking down (rotting). At
this stage (mulm), it is brown, light and in clumps.

Whatever is left after the bacteria have consumed it will either:
a) 'disappear' into a liquid state (dissolved organic compounds or DOCs)
which adds to your total dissolved solids (TDS) in the water,
b) or be a solid indigestible form (silt) which drops lower in the
gravel, typically reaching the glass bottom.
--
www.NetMax.tk

[Elaine T]

NetMax wrote:
> "Derek W. Benson" > wrote in message
> ...
>
>>On Fri, 09 Sep 2005 17:36:31 GMT, Elaine T >
>>wrote:
>>
>>
>>>It's fairly simple. Go anywhere there is an airlift UGF tank that's
>>>been running for more than six months and look under the filter plates
>>
>>>from the bottom of the tank with a flashlight. You will find rotting
>>
>>>debris that will eventually build up to the extent that the tank must
>>>be
>>>broken down to avoid high nitrates and pH crash.
>>
>>I've always found it fairly simple to remove most, if not all, of this
>>brown silt from under the plates on a Ugf. I'd take that 1/4 inch
>>tubing which is used with a pump and airstone and stick it down the
>>riser tube and under the plate and suck on it and siphon out the brown
>>silt.
>>
>>The only stuff I've ever found under a Ugf filter plate is this very
>>fine brown silt, like brown mud but extremely fine small particles.
>>You're sure this stuff is debris which is still rotting? I've always
>>considered this silt to be a leftover by-product of the rotting
>>process; the bacteria have finished with it so it's not rotting
>>anymore, inert matter that the bacteria are done with. I've never read
>>any research or studied this brown silt myself so I don't know, this
>>is just the way I've always thought about it.
>>
>>-Derek
>
>
> My experience agrees with Derek. I've broken down tanks which had a fine
> brown silt under the UGF plates, and I too thought it was a by-product of
> no consquence.

When I've broken down UGF tanks, I've found the same stuff. My thought
was that it was fine particles of food and fish waste that had made
their way below the filter plate, but I didn't do any sort of test to
find out. I'm used to thinking "debris bad - must clean" unless it's in
the root zone of a planted tank but perhaps that's too simplistic.

--
Elaine T __
http://eethomp.com/fish.html <'__><
rec.aquaria.* FAQ http://faq.thekrib.com

[lgb]

In article >,
says...
>
> Detritus is what falls into the gravel. This is a wide collection of
> organic matter, such as feces, scales and uneaten foods.
>
And, I assume, plant debris.

> After some time, it bunches up and begins breaking down (rotting). At
> this stage (mulm), it is brown, light and in clumps.
>
So since some fish prefer a mulm bottom I suppose the stuff is harmless,
assuming normal water change practices.

> Whatever is left after the bacteria have consumed it will either:
> a) 'disappear' into a liquid state (dissolved organic compounds or DOCs)
> which adds to your total dissolved solids (TDS) in the water,
> b) or be a solid indigestible form (silt) which drops lower in the
> gravel, typically reaching the glass bottom.
>
Mine may not reach the bottom, since I have coarse sand, or fine gravel,
choose your preferred term :-). But again it appears to be harmless.

Let me know if my assumptins are wrong.

--
BNSF = Build Now, Seep Forever

[NetMax]

"Elaine T" > wrote in message
. ..
> NetMax wrote:
>> "Derek W. Benson" > wrote in message
>> ...
>>
>>>On Fri, 09 Sep 2005 17:36:31 GMT, Elaine T >
>>>wrote:
>>>
>>>
>>>>It's fairly simple. Go anywhere there is an airlift UGF tank that's
>>>>been running for more than six months and look under the filter
>>>>plates
>>>
>>>>from the bottom of the tank with a flashlight. You will find rotting
>>>
>>>>debris that will eventually build up to the extent that the tank must
>>>>be
>>>>broken down to avoid high nitrates and pH crash.
>>>
>>>I've always found it fairly simple to remove most, if not all, of this
>>>brown silt from under the plates on a Ugf. I'd take that 1/4 inch
>>>tubing which is used with a pump and airstone and stick it down the
>>>riser tube and under the plate and suck on it and siphon out the brown
>>>silt.
>>>
>>>The only stuff I've ever found under a Ugf filter plate is this very
>>>fine brown silt, like brown mud but extremely fine small particles.
>>>You're sure this stuff is debris which is still rotting? I've always
>>>considered this silt to be a leftover by-product of the rotting
>>>process; the bacteria have finished with it so it's not rotting
>>>anymore, inert matter that the bacteria are done with. I've never read
>>>any research or studied this brown silt myself so I don't know, this
>>>is just the way I've always thought about it.
>>>
>>>-Derek
>>
>>
>> My experience agrees with Derek. I've broken down tanks which had a
>> fine brown silt under the UGF plates, and I too thought it was a
>> by-product of no consquence.
>
> When I've broken down UGF tanks, I've found the same stuff. My thought
> was that it was fine particles of food and fish waste that had made
> their way below the filter plate, but I didn't do any sort of test to
> find out. I'm used to thinking "debris bad - must clean" unless it's
> in the root zone of a planted tank but perhaps that's too simplistic.
>
> --
> Elaine T

I didn't analyze it either, but it seemed inert. I let a bit of debris &
algae pile up in the tanks. My thinking is too clean = bad (unless it's
a special application).
--
www.NetMax.tk

[Charles]

On 4 Sep 2005 20:25:54 -0700, "Glengoyne" > wrote:

>I'm fairly new, well returning actually, to this hobby. My family has
>a couple of small 10 gal tanks that we are currently tending. We're
>planning on stepping that up considerably to a seventy gallon or
>possibly a 110 gallon that a friend of mine is possibly looking to part
>with.
>
>When I said I was returning to the hobby, back when I was in High
>School and some of my college years I kept a 55 gallon African Cichlid
>tank. That tank had only artificial plants, an under gravel filter
>system(air driven, not powerheads). I did a 20/25 percent water change
>every other week, cleaning the gravel as I did the water change. I
>supplemented this with a Diatom filter, just about every six weeks.
>Now some twenty years later, I'm told I was doing it all wrong. The
>catch is that I was very successful with the Africans, I even had luck
>raising a few broods of young.
>
>In any case, I'm looking at setting up a new large aquarium, and am
>wondering why not an undergravel system as opposed to the considerably
>more expensive alternatives. Or even why not a UG system to compliment
>a canister filter? The UG filters seem to carry the added bonus that
>they are lower maintenance. I mean, you have regularly clean the
>gravel anyway, don't you?
>
>I'm asking because they (UG filters) seem to be out of vogue, when I
>remember them working quite well.
>
>For the large tank, I'm considering a UG filter setup with a
>couple...or more...powerheads driving the system. The power heads will
>have the added benefit of stirring up the surface of the water to
>assist in oxegenation(sp?) of the water. I will definately be
>employing a Diatom occasionally, as it really did an impressive job
>back in the day. Even if it was just essentially polishing the water.
>Please let me know if I'm nuts.


I'm presently annoyed at my power filters, the UGF/RUGF doesn't turn
into a big white ball of salts in hard water areas.

Re the diatom, consider a magnum filter, or the HOT magnum with the
micron cartridge. It works well to polish the water and is much
easier to deal with that the old diatom filters.

[Rod Bacon]

I am not in a position to really say anything here, as my twin internal
-> RUGF setup has only been running for a month, and only 3 weeks with
any fish. My cycle has just about completed, and overall the water
looks great.

When I do a gravel vacuum and water change, and stir up some of the
crap, making the water cloudy, it only takes about 30 minutes to be
clear again.

The only thing I think I really need to do is to adjust the currents in
my tank to force suspended debris closer to the filters. At the moment,
I sometimes (after feeding) see a cloud of floating matter circling
mid-water in my tank. It's kept in suspension by the upward flow of the
RUGF and takes a while to reach the back corner(s) of the tank where
the water pickups are.

[Tynk]

NetMax wrote:
> "coolchinchilla" > wrote in message
> ...
> > Glengoyne wrote:
> >> I'm still curious about this. When using the gravel vac, does that
> >> remove some of the "mulm" from beneath the tank?
> >
> > When just vacumming the gravel I don't think there's a strong enough
> > suction to get *under* the plates.
> >
> >>
> >>
> >> Most of the negative comments seemed to be related to maintenance
> >
> > Yes, I'd say maintenance is the biggest issue I've heard -- that plus
> > the mulm under the plates.
> >
> >> The gravel gets full of detrius and clogs the plates blocking water
> >> flow to certain locations under the filter. My question to this
> >> is...Well aren't you supposed to vaccuum the gravel anyway? If you
> >> keep your gravel clean, shouldn't that prevent this from occuring?
> >
> > If you vacuum all the gravel throughly, then probably not a problem. I
> > had rockwork in the tank that I didn't tear down every water change.
> >
> >>
> >> First, if
> >> there are "dead" areas in aquariums using UGFs, then why aren't there
> >> "dead" areas in the gravel of other aquariums?
> >
> > Gravel by itself doesn't have water flowing through it. The "dead"
> > areas in a UGF refer to spots under the plates that don't get the
> > proper flow and then anaerobic (bad) bacteria develop there. You can
> > quickly create dead areas by fish exposing the plate. Then all the
> > water starts to go through that exposed part because it offers the
> > least resistence. That leaves corners without decent flow and you get
> > anaerobic bacteria. The strength of the powerhead doesn't make any
> > difference if the plate is exposed somewhere.
>
> My understanding is that the water does flow through the gravel,
> re-oxygenating the aerobic bacteria which coat the gravel.
>
> A dead spot is under ornaments and stones. The UGF pulls detritus
> inwards, and the path of least resistance can become the edges of large
> stones, but then the detritus collects (under something it will be less
> likely to be gravel-vaccumed), and without a flow of water, the bacteria
> developed are anerobic. A little anaerobic bacteria is of little
> consequence. Some filter systems even encourage it, but pockets of
> anerobic activity produce nasty gases which can be very toxic to fish
> when the stone is picked up. This is especially bad under the slate used
> with driftwood.
>
> Pros/cons of operating with or without a UGF ironically come down mostly
> to the mechanical filtration, not biological. Without a UGF, but with
> good mechanical filtration, the detritus has a better chance of being
> brought out of the tank into a filter media which gets cleaned
> periodically. With a UGF, it collects in the gravel and convert to
> dissolved organic compounds (DOCs). The RUGF operates identically, but
> due to the reversed current, the detritus does not settle so deeply,
> theoretically making it easier to gravel-vacuum.
> www.NetMax.tk
>
> > HTH.
> > coolchinchilla

I tossed out every one of my UGF's 18 yrs ago.
Seemed like no matter how well or often I vacuumed the gravel, I still
had too much crud under it, creating a cesspool just waiting to release
it's toxic gas.
So out they went with the trash.
I simply vac the gravel more often. With weekly water changes and
gravel vacuuming 2-3 times a month, I've had better conditions in my
tanks than before with the UGF.
However, I do have a gazzilion MT smails in the gravel giving it a stir
here and there. If you look closely, at any given moment, you can see
the gravel moving (smails under the gravel that are hidden from view).
This freaked me out before I realized it was the snails, lol.
NetMax is right on, it all comes down to the keeper's tank maintenance.
I'll never waste money on an UFG again. Never.
You take a flashlight and look at the underside of my tanks...they're
all as clean as could be.
I've not seen that with an UGF going, just a lot of gunk. (That's more
than just my tanks too.)