Opinions on Under Gravel Filters

[Goosedub]

Hey all,

 

wondering if anyone out there uses under gravel filters. Opinions? Actual experience? I’m thinking About a planted set up that has minimal energy requirements while also being visually appealing. UGFs seem like they would work well in this circumstance.

[FriendlyLoach]

I am sorry, I have not used a UGF but I was thinking about it... and they said that plant roots can stop water from going down through the filter. 

[FishyJames]

I use an under gravel filter in my planted 29 (set up for only 2 months).  So far so good.  I used 3 inches of eco complete to help keep the roots further away.  If in 5 years the filter gets clogged, i will pull the tubes and install a hang on filter.

[Frank]

I used one a long time ago. It seemed to work great. I only used it for a few or six months, though. I don't remember what I did. Maybe I got a new air pump. When I turned it on, there was wayyy too much airflow. It filled the tank with every bit of crud that was under there. It was a lot. I swore off of them, after that.

[Goosedub]

15 minutes ago, FriendlyLoach said:

I am sorry, I have not used a UGF but I was thinking about it... and they said that plant roots can stop water from going down through the filter. 

Interesting. Those would be some thick roots. I have heard they are really good for plants because they pull the nutrients in to the roots. 

[Goosedub]

10 minutes ago, Frank said:

I used one a long time ago. It seemed to work great. I only used it for a few or six months, though. I don't remember what I did. Maybe I got a new air pump. When I turned it on, there was wayyy too much airflow. It filled the tank with every bit of crud that was under there. It was a lot. I swore off of them, after that.

How long did you wait to see if that crud would clear up?

[Celly Rasbora]

I've used under gravel filter systems, as my LFS back in the day swore by them. When I set up my 5 gallon a few years ago, that was my initial filtration system, but I wound up with a HOB to supplement, as I like the mechanical filtration and water flow it provides.

I recently discovered the Aquarium Co-Op sponge filter, though, and that is what I have in my tank right now. Honestly, I don't love the idea of all that gunk under the gravel and the sponge filter is super easy.

[JaredL]

I use an undergravel filter in my 29gal. Layered baked clay(oil dri), seachem flourite, more baked clay, capped with fine gravel. In total its about 4inch(a bit more than I intended. Cut my lift tube to be barely above gravel to reduce flow.

My goal was to follow instructions from Dr. Kevin Novak with the purpose of promoting de-nitrifying bacteria.

After a few months my plants have been doing great. I think the key to undergravel filters is to not try to force tons of water through them. However, I don't use this as my primary filtration. I also use a canister filter for mechanical filtration as well as promoting nitrifying bacteria. 

[lefty o]

they arent fancy, but they do work. long ago when i was a kid, the 2 choices were under gravel or a box filter, and while they have gone out of style, they do a decent job.

[MickS77]

I'm running one on each half of my 75 gallon. One half is connected to a canister filter and the other is run with air. I have a few crypts growing in it nicely. 

[Tamitha]

I’m using an under gravel filter for a heavily planted 55 gal, going for two years now. I can see the underside of my tank and so far there is no buildup. I also run one on a lighter planted 40 breeder, going on about 18 months or so. Neither tank has any other filtration. 

[Frank]

1 hour ago, Goosedub said:

How long did you wait to see if that crud would clear up?

 

I don't think I waited, at all. That was forty-five years ago. I don't remember how I cleaned it up. 

I left the filter there and got a hang on back filter.

[Anita]

https://aquariumscience.org/ has quite a bit of information on under-gravel filters (UGF), including efficiency ratings of various types of filters. The website author, a chemist, cites articles from peer-reviewed academic/scientific journals. He presents the information in a tiered format—from Aquariums for Dummies to Bill Nye the Science Guy. As a former lab tech, I appreciate the inclusion of scientific papers, although admittedly I do not feel the urge to slog through them myself.  Zzzzzz..... Thankfully, the author has done this for me. 😍

Be prepared to read some controversial notions. The author unabashedly accepts the labels, "contrarian" and "chip on his shoulder." From his intro page:

Quote

Because the author calls out all the many parroted myths of social media, many say he is a “contrarian” (“a person who opposes or rejects popular opinion”). Because the author doesn’t like fake “marketing hype” and calls it out whenever he sees it, many say he “has a chip on his shoulder”.  The author pleads guilty to both charges. We list over 100 separate instances where we reject “popular opinion” because the “popular opinion” is not supported by the science. We also list 19 separate instances where we reject “marketing hype” as it is not supported by the science.

 

 

The first paragraph from the Review of Aquarium Filters page gives you an idea of website's tone:

Quote

One Big Scam

Any discussion of ANY filter requires a disclaimer. ALL commercial filters almost without exception tell the owner to replace the filter media (Cartridges, sponge, ceramic rings, carbon, Matrix, etc.) on a regular basis, once a month, once every three month or once every six months. Supposedly this is because the media becomes clogged and dirty. And the media is ridiculously expensive. We must emphasis:

Replacing the Filter Media is a Big SCAM!!!

Yes, there is absolutely no reason to replace the media on a regular basis other than to make a lot of money for the supplier of the filter.

 

Have fun! 🤓

[ChefConfit]

I inherited one with my 29 Hex and immediately threw it away. My hex is dirted so that would probably not have gone well.

My 2 concerns with using an ugf in a planted tank would both take months or years to become a problem.

1 plant roots clogging the filter. If you only have a few plants this probably won't happen, but I like to plant very heavy and from seeing how thick the roots get when I've broken down a tank I know it's a possibility.

The other would be if using an aquarium soil it will eventually break down, get sucked in and then the uplift tube starts spewing mud everywhere. The second is easily prevented by using only gravel, but a lot of planted tank people like their planted substrates. 

[CT_]

1 hour ago, Anita said:

https://aquariumscience.org/ has quite a bit of information

I like that website a lot but I have reason to be skeptical of some of the things there so don't take it all as hard truth, or even science, take it as another resource.

I love his advice on using pot scrubbers as filter media though.  I'd use them except I already have a lot of sponge that's good enough and will last forever

[MJV Aquatics]

Undergravel filters get a bad rap. In reality, they are great when operated and maintained properly...otherwise they can become a nitrate factory.

> The gravel needs to be 3-4" of medium to small grain size as large gravel lets too much 'stuff' to get pulled down under. Even coarse sand could be used along with a layer of weed fabric on top of the UGF plates.

> The air flow needs to just be moderate. At some point folks thinking they'd get more filtration upped the air pulling water too fast through the gravel only to draw decaying organics deep in the gravel and under the plates. Modest air flow pulls water slowly and gently through the substrate.

> Like any filter, it needs to be maintained by routine gravel vacuuming to remove unwanted waste (just like you'd service any filter). This may not be necessary with fine substrate material. (e.g. if I was to use a fine gravel or coarse sand with a modest air flow, water pulled through the substrate bed would be slight and not pull organic solids down under). 🙂

[Elquinjena]

when I started keeping fish, an under gravel filter was the only way to go. Any of those new tank set ups had one in it.

I still use them, and I have tied them to my hang on the backs, using the uptake tube to pull from the under gravel filter.
I also have planted tanks with root type plants ( doing very well with crips ). I do use a bigger hang on the back than what the tank size is, on a 20 i have a 30 gallon one, so it has a bit more strength to pull the water down through the gravel and back up the tube.

I still gravel vac down to the gravel grate and pull some of the stuff out from there but it is getting to the point where i can longer with water changes.

I also use sponge filters and between the two my water is crystal clear.

 

[Goosedub]

11 hours ago, Tamitha said:

I’m using an under gravel filter for a heavily planted 55 gal, going for two years now. I can see the underside of my tank and so far there is no buildup. I also run one on a lighter planted 40 breeder, going on about 18 months or so. Neither tank has any other filtration. 

Wow, this is encouraging

[Goosedub]

5 hours ago, Elquinjena said:

I still use them, and I have tied them to my hang on the backs, using the uptake tube to pull from the under gravel filter.
 

How do you tie them together?

[Flytrap]

I used one in my planted freshwater tank that was already “seasoned” many years. Upon moving I visited a local pet shop and I saw the Penn Plax under tow UGF. I reset up the tank and the plants and fish thrived!!! I did regular water changes and can say everything was much healthier than before using it. I recently saw Cory’s talk on ugfs from 4 years ago and his presentation on the new set up for the guppies and platies. He used a Lee’s but don’t know if it was a premium or original model. Does anyone know? 
Thank you all and Cory Thank You for all of your information. 
Flytrap

[Anita]

And there's...

 

[Celly Rasbora]

12 hours ago, Frank said:

 

I don't think I waited, at all. That was forty-five years ago. I don't remember how I cleaned it up. 

I left the filter there and got a hang on back filter.

I've made the gunk from under the filter come up into the tank by putting the air stone too far down. It doesn't take long to resettle, but I think that speaks to my unease with the system. I never know exactly where the sweet spot is for the air stone.

[Flytrap]

Hi all,

I used an under gravel filter on a tank that had already been running for many years.  I moved and the nearby pet shop had ugf's and I reset the tank using the same gravel etc.   The tank was a freshwater planted with livebearers: platies, mollies, guppies, etc.  Everything thrived with the under gravel filters and I never had any problems.  I did regular water changes.  So I think they are great.  I've since set up a 285 gallon tank with a sump with breeding Kribs and livebearers.  I had forgotten all about ugf's and also read that they were considered a bad choice.  After recently seeing Cory's talk on UGF's and then his set  up for platies and guppies using one.  He was using a Lee's.   Does anyone know if it was a Lee's premium or original model.

Thank you all and of course Thank you Cory for all of your information.

Flytrap

[gardenman]

I'm a believer in UG filters though I'm not currently using one. My old marine tanks used to flourish with the Nektonics UG filters. The only issue I have with traditional UG filters is that you're not necessarily using all of the gravel as a medium. Water will take the path of least resistance which means areas nearer the lift tubes will get more flow while those farther away may get none. A reverse flow system where filtered water (to remove the suspended gunk) is pumped under the plate of a UG filter and then flows up through the gravel under some force largely solves that issue if the volume of water being pumped in is adequate. 

Another solution to that might be to have an S-shaped snake-like open channel under the UG filter where air gets pumped in at one end then flows through the snake-like shape to the outlet tube. In theory, this air movement could grab water all along the air channel and pull it to the outlet. The fresh air though could also stratify somewhat and only the air at the top of the channel would move through the system leaving the air/water lower in the channel undisturbed. Some baffles here and there would solve that though. 

The University of Delaware made a booklet titled "Keeping A Marine Aquarium" by Christopher Valenti many, many years ago that showed how to make your own UG filter. (No copyright date so I don't know when it was published, but in the 70s feels right. To give you some idea of how long ago this was published, the filter recommended to supplement the UG filter was a Dynaflo and was expected to cost $15 for a 20 gal tank.) I may try making a DIY UG filter using their plan and then adding some sliced PVC to make the air channels and see how it works. 

[Celly Rasbora]

8 minutes ago, Flytrap said:

Hi all,

I used an under gravel filter on a tank that had already been running for many years.  I moved and the nearby pet shop had ugf's and I reset the tank using the same gravel etc.   The tank was a freshwater planted with livebearers: platies, mollies, guppies, etc.  Everything thrived with the under gravel filters and I never had any problems.  I did regular water changes.  So I think they are great.  I've since set up a 285 gallon tank with a sump with breeding Kribs and livebearers.  I had forgotten all about ugf's and also read that they were considered a bad choice.  After recently seeing Cory's talk on UGF's and then his set  up for platies and guppies using one.  He was using a Lee's.   Does anyone know if it was a Lee's premium or original model.

Thank you all and of course Thank you Cory for all of your information.

Flytrap

Cory holds up the packaging of the Lee's filter in the video Anita embedded above. Your answer is in the rant at the end of the video.