How Do Undergravel Filters Work?

[GeordieFishLover]

How do these work and how often do there need cleaning?

 

[tom_os]

the basically pull water in through the gravel so the gravel is the mechanical and biological filtration. it then goes up a pipe to the top of the tank where the clean water comes out

if im correct they need alot of maintenance and are quite ou dated now. also they arnt as effiecient as other means of filtration

 

[aaronnorth]

http/www.fishforums.net/index.php?showtopic=288217&hl=

 

[Sarah5098]

Sorry to jump on your thread but the lfs set up my ugf for me, but i think they completely f***ed me over. I bought the tray and collum things, but then they attatched an air pump to it and put the air stones in the collum.
I personally dont think this works as the air just bubbles out of the air stone and i see no filtration going on at all.
I then found this site and am now awaiting delivery of a fluval 3+
Luckily i am only cycling so no fish were harmed! Waste of bloody money though!
Sarah

 

[GeordieFishLover]

Sorry to jump on your thread but the lfs set up my ugf for me, but i think they completely f***ed me over. I bought the tray and collum things, but then they attatched an air pump to it and put the air stones in the collum.
I personally dont think this works as the air just bubbles out of the air stone and i see no filtration going on at all.
I then found this site and am now awaiting delivery of a fluval 3+
Luckily i am only cycling so no fish were harmed! Waste of bloody money though!
Sarah

the filtering happens under the gravel

 

[Strangerover]

Although they are out of fashion now....

I had one years ago..

It works very well if set up right....

As said the water is pulled down through the gravel, this acts as both a physical and biological filter.

The tube is how water is sucked through, either by an airstone or powerhead..

The top of the tube needs to be either level or under the surface of the water as air bubbles will move water but not very strong...

Down sides.....

The gravel needs to be kept clean .. I used sparce feeding of the fish and bottom feeders to keep the poo at bay...

Plants often don't like the water flow through the roots that way...

Although its out of fashion and for high population tanks they need a fair bit of work... they can be very good from my experience

I had a 3ft tank for about 5 years and always had grystal clear water and my fish lived well... and bred !!

Now I have a Fluvan canister 305 and a U4 filter.... because I couldn't find an undergravel !

 

[keenonfish]

I still use one and find it is great Just keep stocking low and everything will be fine!

 

[RadaR]

Personally I think they are awful.
3 types of media in filters. Mechanical, chemical and biological. Gravel performs poorly for all of these. Don't skimp on equipment, invest in a good filter.

 

[bagu]

i have a UGF in my 20gal, set up for 5-6 months now alongside a 3stage inbuilt filter...

i love the UGF, i am gonna clean it end of this month

 

[nitro7]

i have a UGF in my 20gal, set up for 5-6 months now alongside a 3stage inbuilt filter...

i love the UGF, i am gonna clean it end of this month

the only trouble with u/gs is you get a lot of gunk lieing under the filter plate,so when you clean your gravel you get a lot of it going back into your tank,plus you will find it hard to grow plants in it,you can get rid off the air stone and fit a power head ,

 

[nitro7]

did you know that the ug became the first internal power filter,by removeing the air stone and replaceing it with a power head it became the first internal,silent filter

 

[OldMan47]

I am seeing a lot of misinformation here on the UGFs. I no longer use them but they are very good biological and mechanical filters. By using a deep bed of gravel as a filter element they provide a surface that is unrivaled for the biological filter to develop. The air bubbles do not just bubble up the tubes. the bubbles in the risers carry water along with them at a rate that gives the substrate lots of contact time with the tanks water. If you have the water level close to the top of the riser tube, you can easily see the large flow that a properly adjusted UGF is moving through the filter media. It is a necessity to use the right substrate and to make a fairly even depth bed of it but if that is done and the gravel gets a decent vacuum every week or two, the filter can take care of your tank with no help from any other filters.
I no longer use the UGF because I like being able to vary the depth of my substrate and not worry about it affecting my filtration. For that reason I use sponges and canisters in most of my tanks. I also run one tank with plants acting as my biological filter. I like that tank so well that I am setting up my newest tank to use a true biological filter, plants.

 

[Sarah5098]

So was my UGF set up wrong then? Do the air stones need to be at the bottom of the collumns and not at the top?
Thanks
Sarah

 

[Sarah5098]

Sorry to jump on your thread but the lfs set up my ugf for me, but i think they completely f***ed me over. I bought the tray and collum things, but then they attatched an air pump to it and put the air stones in the collum.
I personally dont think this works as the air just bubbles out of the air stone and i see no filtration going on at all.
I then found this site and am now awaiting delivery of a fluval 3+
Luckily i am only cycling so no fish were harmed! Waste of bloody money though!
Sarah

Haha! Feel like such a trollop now! My 1st ugf was in working order. Unfortunately when they set it up for me they left the air stones at the top of the collum, obv wont do much there! Sorry to be such a boob