# how do undergravel filters work?



## charles_316 (Jul 6, 2004)

i have an undergravel filter but am not sure how it works...

there are four white base pieces.... two of them have pipes coming out of the corners.... i believe these two go in the corners of the tank...

but do i have to connect anything to these pipes or how does it work?


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## P-Power (Jan 23, 2004)

the undergravel filter works by drawing water through the sand/gravel bed. So, you need sand or gravel on top of the platform thing, and something to draw the water up through the tubes in the corners. Cheap ones use a bubbler to draw the water up, but you can also use a powerhead.


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## elTwitcho (Jun 22, 2004)

And the gravel then traps debris where it gets broken down by bacteria. Other bacteria on the gravel bed take part in the ammonia-nitrite-nitrate process as well, so the gravel basically serves as a big sponge you pass water through.


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## rchan11 (May 6, 2004)

But an undergravel filter is a pain to clean.


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## charles_316 (Jul 6, 2004)

how do i clean it ? do i have to remove it ?


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## elTwitcho (Jun 22, 2004)

charles_316 said:


> how do i clean it ? do i have to remove it ?
> [snapback]998486[/snapback]​


Yes because all sorts of sh*t will build up under the plates and really mess up your water quality. It's best not to use them at all.


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## Piranha_man (Jan 29, 2005)

I couldn't agree more with Twitch.
I had an undergravel filter in my 150 gallon pygo tank for 4 months powered by 3 402 Powerheads.
I would vacuum the gravel weekly but last week I was looking at the underside of the tank from inside the cabinet stand and was floored by the amount of detritus that was under those plates!
No wonder I've had such a battle with nitrate levels!

2 days ago I siphoned out 25% of the water and pulled the plates and the water was absolutley black with detritus.
I vacuumed and changed out 50% of my filtration media because it was becoming clogged with the now free detritus. (I left half the media so as to not disturb the bacteria) and have now got the gravel pretty much free of detritus and the filters are in order.

I feel very good about this decision to remove my undergravel filter.
I believe they're a ticking nitrate bomb.


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## 90blackcrx (Mar 30, 2005)

I got rid of my under ground filters, were to much of a pain and they really did not help keep the tank any cleaner then it is now with just a normal filter


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## sicklid-holic (Mar 25, 2005)

I wont use it. Undergravel filter is a dino age filtration, that is a junk. Bad for the fish overall. 
If you want good filters go w/ wither AC300, AC500, Emperor400
and for canisters go w/ XP3
Now your filtering!!!


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## CTREDBELLY (Apr 8, 2005)

i would not use the UGF its a pain in the ass to clean you will have issues with water quality and clarity. remeber its drawing crap deeped into the gravel bed most of it staying there under the plates so even a gravel vac cant get it. then whats cleaned is sucked up my the power head shoting crap back into the water fo rthe main filter to clean making slightly cloudy water. also if u have a planted tank its more of a pain if u want to remove it later for trouble cause the plants roots will grow in the plates and u will destroy the roots if your need to remove it.


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## mori0174 (Mar 31, 2004)

Basically what the others said, they dont work.


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## Kevinr (Feb 5, 2005)

Time to play devils advocate here, UGV's are ok on smaller aquariums but do have their draw backs. For the larger ones I'd stick with internal/external filters. For substrate you need a medium size gravel and should cover about a quarter depth of your tank (sand wont work as it clogs up the holes in the filter plate) and a decent powerhead or airpump with finegrain airstones. The lift tubes should be at least 6" tall, taller is better as it provides more draw for the water - the other problem with UGV's is the lift pipes, unless you can hide them, they look awful in a tank. UGV's require a higher maintenance routine, with regards to syphoning the tank, you will need a vacum hose for it, this will allow some of the gravel to travel up the pipe without syphoning it away with your water. As for the crap underneath, it will have a slight effect on your water, but as long as you keep on top with your water changes and other maintenance, you have little to worry about, but you won't get the clarity of water like you do with other filters.

For the UGV to work, you need to place either a power head on top of one or both of your lift tubes, or feed an airstone and airline either up through the bottom, or straight down the top of the pipe


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