Under Gravel Filter-Talk Me Out Of It

[Ken]

I'm setting up a new 20L. I like what sponge filters do in my other tanks (no ammonia or nitrite ever) but I don't want to try to hide them in this tank. I am not going to spend the money or put up with the cleaning headaches of a canister. HOB's are quite limited (in my mind) for biological filtration. So it seems to me under gravel filters fill the bill. So, why not? Is there something even better and easier I'm missing?

[lefty o]

HOB's can be set up to be good biological filters, but there is nothing wrong with an under gravel filter. they work just fine. filtration really comes down to pick your poison.

[Mitch_ScruffyCityAquatics]

I’ve always wondered how an under gravel filter would impact using root tabs. 
 

if you aren’t doing a planted tank it shouldn’t be a problem, but that was my first thought. 

[Bean]

How do you clean an undergravel filter?

[Ken]

52 minutes ago, Mitch Norton said:

I’ve always wondered how an under gravel filter would impact using root tabs. 
 

if you aren’t doing a planted tank it shouldn’t be a problem, but that was my first thought. 

The water moves down through the gravel. I was hoping would no longer need root tabs, some EZ Green and you're good to go? 

[Ken]

51 minutes ago, Bean said:

How do you clean an undergravel filter?

Back in the old days I gravel vacuumed, that was with plastic plants and goldfish. I wonder if with smaller less messy fish and live plants maybe I just could just let it go.

[Bean]

5 minutes ago, Ken said:

Back in the old days I gravel vacuumed, that was with plastic plants and goldfish. I wonder if with smaller less messy fish and live plants maybe I just could just let it go.

As in never clean it?

[Brandy]

At some point you might get a mat of roots, which would slow your flow. That is the only issue I can really think of. It depends on whether you plan to plant thickly and how many roots your particular plants want to put out. 

Edited November 30, 2020 by Brandy

[Ken]

7 minutes ago, Bean said:

As in never clean it?

Yup. Lots of good stuff for plants in that mulm. What I would hope is that with some root feeders and some water column feeders I could just let nature break everything down and hit a nice balance. Or maybe I would kill the whole tank? The idea of an easy to maintain tank without a bunch of equipment appeals to me. I'm hoping to spark some conversation with this.

[Fonske]

1 hour ago, Ken said:

The idea of an easy to maintain tank without a bunch of equipment appeals to me

Depending on how much fish you plan to keep in the 20g, a heavily planted tank with some floaters and no filtration at all might be an option. 

[Maggie]

I don't know anything about under-gravel filters but it seems like it would be a huge task to possibly have to empty and completely disassemble your tank if you run into problems.

[Paul]

You’ll have as many issues with an under gravel filter as you will with a sponge filter which is pretty close to zero.

[David W]

I have no problems with under gravel filters. Just throwing in some good info on making HOB filters work like sponge filters.  

[Mitch_ScruffyCityAquatics]

10 hours ago, Ken said:

The water moves down through the gravel. I was hoping would no longer need root tabs, some EZ Green and you're good to go? 

It would definitely depend on your plants. Heavy root feeders would most likely struggle, but column feeders would be fine. 

[Mitch_ScruffyCityAquatics]

10 hours ago, Ken said:

Back in the old days I gravel vacuumed, that was with plastic plants and goldfish. I wonder if with smaller less messy fish and live plants maybe I just could just let it go.

I have a panted tank and I don’t vac the substrate. I want all that poo to get into the gravel and feed my plants. 
 

I do still change water, but I would live to get to the point the plants take care of it all. 

[Ken]

11 hours ago, Brandy said:

At some point you might get a mat of roots, which would slow your flow. That is the only issue I can really think of. It depends on whether you plan to plant thickly and how many roots your particular plants want to put out. 

I hadn't thought of that, I'll bet it can happen fairly quickly if the plants are growing well.

[Ken]

9 hours ago, Fonske said:

Depending on how much fish you plan to keep in the 20g, a heavily planted tank with some floaters and no filtration at all might be an option. 

That is an option that would be fun to try someday. Not yet. I struggle with balancing an aquarium with all the help filters give you. I'm always awestruck watching LRB.

[Andy's Fish Den]

Years ago, as like 20+ I ran an undergravel filter in a 150 gallon tank I had set up. It was heavily planted with jungle val and sword plants and they grew like gang busters in that tank. This was before I knew anything about fertilizers, root tabs etc, I just planted them in regular natural colored aquarium gravel and they grew like mad. I never gravel vac the gravel, when I did water changes, I just drained the water and added it back with a Python system.  The water was kept at 82-86 degrees because I had wild caught discus and angels in there, I would pull handfuls of jungle val out every month to take to my local fish club meetings to sell,

[CanadaAmanda]

I just put in a UGF in a tank I'm setting up.  I'm hoping it will be low maintenance, and plan not to use root tabs, as the stuff getting actively sucked down into the gravel should feed the plants, and it'll be oxygenated so it'll be breaking down faster than in regular substrate. I love the idea of all the gravel being my filter media without having to add any additional filter media that needs servicing as this is a smaller tank.  I also like that it will agitate the surface and that it's run by air - so easy to deal with power outages.  The only thing is that adding any chemical filtration can be a challenge... the carbon filters you can plug into the uplift tube seem to screw up the bubble flow, but I should only need to do that a couple times a year, so I can live with it.

 

I've been eager to try out UGF after learning about them, and looking forward to learning more about it through this experience!  Since it was a small set up, I've still got a ton of plates and an uplift tube... so I'm set for the next smaller tank too! 🙂

 

One thing to consider is that you do have to use larger sized gravel.  I was initially hoping to use black sand in this project but opted for black gravel to accommodate the filtration.

[CanadaAmanda]

Oh and I also like that it's good for fry - no additional considerations needed.  The only thing I know of that might regularly swim into the uplift tube is a khuli loach... those things are so weird and curious.  I'm interested to know how it would perform with fish that drop eggs into the substrate.

[Kirsten]

I was interested in trying an undergravel filter, but decided against it when I read it can lead to sludge build-up and dead zones. I definitely prefer a simple, easy-to-clean sponge filter or coarse sponge media in a HOB filter with lots of plant growth.

Edited November 30, 2020 by Kirsten

[Gideyon]

@Ken, did you ever do this?  Just curious on how it worked out

[Eric R]

UGFs seem to used to be really common but have fallen out of fashion. Can't say I have ever tried one or really even know a lot about them. Most surfaces in your tank, especially plant surfaces, help with biological filtration. Sponge filters, HOBs, and canisters can provide varying amounts of mechanical filtration. All three work fine for me.

[Jeff]

What about a small sump?

[Ken]

6 hours ago, Gideyon said:

@Ken, did you ever do this?  Just curious on how it worked out

No. I decided I wanted to have a sand in the front of the tank with the size of the gravel graduating up as it went back in the tank. Like MD does in a lot of his videos. You just can't run an undergravel with sand. I still think an undergravel filter is a good idea. I don't know why all the Betta people don't use them, it seems like a perfect fit.