Under Gravel Filters - Do They Work?

[jlw]

I'm still kind of new to the hobby. I got a 20 gallon tank for Christmas (replacing my 10 gallon). I'm getting ready to set up the tank but if these are worth the investment then I obviously need to make that purchase before I put the gravel and plants into the tank.

 

[eaglesaquarium]

Undergravel filters do work, especially if properly maintained. 
 
 
That said, undergravel filters and plants don't mix.  So, if you are going to be adding live plants, you will want some other type of filter.  Inexpensive options are 'Hang on the Back' filters.  More expensive options would be 'canister filters'.  You could go with an internal as well, but I don't like those as they are quite conspicuous in the tank.
 
 
Some (HoB) options for that size tank: AquaClear, Penguin, Emperor, and Whisper.
 
Personally, I don't think that a canister is necessary on a tank as small as a 20.

 

[DrRob]

They do work,they work very well, but they're quite maintenance heavy in the long run. You need to have a good regime of cleaning to keep them flowing well and not have too many dead spots.
 
They're also not that amazing as mechanical filters, so if crystal clear water is your thing they're not ideal.
 
I've found, over time, that plants mess with them as well, and vice versa.
 
Closest filter otherwise is the Hamburg Mattenfilter, that doesn't mess with the substrate and is also fairly poor for mechanical while being amazing for biological.

Personally, I don't think that a canister is necessary on a tank as small as a 20.

 
and here we see the UK trend and the US differ. I have an external on my 30 litre tank, and have found it the most important one I have, giving the greatest percentage increase in water volume for the tank, and removing kit from a tank that is already quite small. I've also found that internals clog faster the smaller that they are, so the small internals require more regular cleaning.

 

[jlw]

Great advice. Exactly what I was looking for. I like the look of the planted tank so I think I will steer clear of the Under Gravel filter. Going to the pet store today to start getting some supplies. Then I'm going to try a fishless cycle!

 

[eaglesaquarium]

Personally, I don't think that a canister is necessary on a tank as small as a 20.

 
and here we see the UK trend and the US differ. I have an external on my 30 litre tank, and have found it the most important one I have, giving the greatest percentage increase in water volume for the tank, and removing kit from a tank that is already quite small. I've also found that internals clog faster the smaller that they are, so the small internals require more regular cleaning.

 
I'm cheap.   For the upfront cost, I'd rather do a bit more filter cleaning, but that's just me - which is why I added the 'personal' note.

 

[Tongue_Flicker]

Undergravel filters work best when you use large grained gravel or pebbles as substrate, allowing a more 'porous' circulation. Using floating plants, and feeding floating pellets or flakes/slow sinking fish food would make your maintenance waaay easier

 

[Alasse]

Ive had a planted tank with an UGF, it can be done.
 
Canisters are cheaper for me to buy than HOBs. I just picked up a canister for my 7.4gal tank. I didnt want an internal taking up more space.