Undergravel filters are not bad
I recently joined this forum and was somewhat surprised by the number of hobbyist who dislike undergravel filters. I have had a conventional one in every tank since the 1970's, and since this adds up to dozens of undergravel filters over several decades, I thought I might be qualified to clear up a few concerns. I only went to reverse flow a week ago, (Thanks for the advice, Bryan!), but can already explain some amazing benefits of this set-up too. This is my opinion based on many years of experience and I am entitled to it. If you feel otherwise, don't flame me. Instead, post a response expounding your own experiences and let the readers decide for themselves.
From what I can tell, the most common undergravel concerns are: 1) They are "old technology" and have out-lived their usefulness in the hobby. 2) They offer poor filtration. 3) They are not suited for growing live plants. 4) "Muck" collects underneath them and is impossible to remove. 5) They clog up constantly, fouling the tank and creating maintenance woes or killing the bio-mass of beneficial bacteria. 6) They are hard to clean.
In the same order, here are my responses:
1) They are old technology for sure, but this alone is a ridiculous reason to avoid them. The latest, most expensive and complicated solutions are not always the best answer to life's simple problems.
2) They do offer very poor mechanical and chemical filtration, but when properly maintained the biological benefits are huge. And remember, biological filtration is the most important and the one you can never have too much of. In conjunction with a good power filter, they do offer worthwhile benefits.
3) I am not a horticulturist, neither in gardens, pots, nor aquariums, so I wouldn't argue with this except to say that not everyone cares about it. That most all tropical fish will thrive in unplanted tanks with 3 different types of filtration (biological, mechanical, and chemical) along with regular partial water changes is an established fact. I prefer the look and convenience of artificial plants, and undergravel filters are fine for this. I also enjoy replacing my expensive bulbs only when they refuse to light up - about every 5 years and sometimes much longer.
4) Totally agree, but not a problem with pre-filtered, reverse-flow powerheads.
5) Not if kept clean. And again, not much of a problem at all with pre-filtered, reverse-flow powerheads. These push only filtered water through your undergravel filter solely for the benefit of biological filtration and do nothing to clog the substrate. Indeed, the reverse flow option may even keep gravel cleaner than using nothing because it discourages floating debris in the tank from settling in it.
6) Hogwash. Until last week I had used a conventional undergravel filter in every tank I have owned (about 25 total) for well over 30 years, and sometimes nothing else. And as long as I did not over-feed the fish, the gravel only needed cleaning about once a month and could be stretched to twice that in under-populated tanks. This is done during bi-weekly water changes and adds no extra time to this simple responsibility. All you need is a bucket and a simple, inexpensive gravel siphon. Coincidently, the siphon tool actually makes scheduled water changes much easier and is probably something you will want to own anyway.
I have a theory that undergravel filters earned their poor reputation in the past, and mainly for symptoms relative to a fault which I have never even heard discussed: Conventional ones did encourage over-feeding, especially if there were bottom feeders in the tank. Any food that was targeted at bottom feeders was quickly sucked into the gravel and out of reach of the hungry fish where it fouled the filter media (gravel) prematurely and caused maintenance headaches. The lowest fish starved though plenty of food hit the bottom only to disappear into the gravel. I learned quickly it was better not to keep bottom feeders than to foul my undergravel filters trying to get enough food to them. For this reason I have had a decades-long happy affair with even conventional undergravel filters, though I am certain most aquarists continued to over-feed and hated them. Again, the advent of reverse-flow has totally eliminated even this problem for attentive aquarists.
Though I have done it many times and for years at a stretch, I do not recommend using undergravel filters as the sole means of filtration. Canisters and power filters are just too inexpensive and good these days to not have one on every tank - at least for primary mechanical and chemical filtration. (I prefer hang on the tank power filters for their unmatched ease of cartridge maintenance and lack of hoses and connectors.) However, unless you want live plants rooted in fine, fertile substrate, adding a reverse-flow undergravel filter to an already good freshwater system does make it better.
Look at it this way - You already have gravel in the bottom of your tank and it should be cleaned occasionally anyway. Why would you choose not to circulate a supply of clean, oxygenated water through it for the benefit of critical biological filtration? This is probably the largest surface area in the tank. It seems a shame not to use it as anything more than decoration.
Sponge filters seem to be all the rave these days and enjoy much praise for their superior biological qualities. But they are UGLY, and take up waaay too much room in the tank, at least in my opinion. And they must be regularly removed from the tank and replaced, or at least rinsed and squeezed out in a sink, totally disrupting the bio-mass. Not so with an easier-on-the-eyes undergravel filter. It remains inside the tank forever - even during cleanings - with it's bacteria mostly in tact, so there is much less chance of harmful toxins ever spiking and killing your prized fish.
And one more thing concerning undergravel filters used in conjunction with power filters for extra biological filtration - they can be run with a cheap, battery operated air pump during power failures. This has saved my fish more than once. During an interruption, power filters stop and their bacteria quickly die off, but undergravels can be kept in emergency service rather cheaply.
Listen, aquariums need all the biological filtration they can get. You can't go wrong by adding a simple, effective, undergravel filter to your fish's life support system. And they do have their benefits over other types of filters. The more I research other methods, the better I like my undergravel filters.
Hope this helps somebody.
My little 3-gallon plastic tank came with an undergravel filter. I successfully kept a couple of guppies in there for ages (before I knew that guppies should be in a bigger tank), until a tube thing broke and I couldn't find a replacement. That's something I would NOT want to do on a big tank - remove or replace an undergravel filter.
When I moved my fish into a bigger tank, I rinsed all but a cup of gravel. There was muck in the gravel even after weekly water changes and gravel siphoning. I think there is a certain amount of muck that'll drop to the bottom of the tank regardless of your filtration system.
I thought the issue with the plants was that the roots could clog up the slits in the filter. I can imagine that a plant with a fibrous root system could plug things up pretty quickly (but that's just going by what I know of terrestrial plants, I'm a novice when it comes to my aquarium plants.)
I like your point about having the oxygen circulating through the gravel. My tanks are all set up now so I won't be getting an undergravel filter in mine, but you've certainly made me reconsider their value. Interesting.
Nothing wrong with reverse flow UGF IMO, most of what you say is correct, but.....
All you need on any tank at the MOST is biological and mechanical filtration, the properly setup tank can void both of these things. Chemical filtration is never necessary. The vast majority prefer live plants since they come with many benefits. If you are using T8 bulbs these are cheap to replace unless you fall to marketing, only expensive bulbs in this hobby are power compacts, T5's, metal halides, LEDs, ect.
You hit my big beef with UGF "it stays in the tank forever" I am much happier to stick with my ugly sponge filter that takes up to much room. It goes in and out in minuets. Also I can build a sponge filter with mostly garbage+ a powerhead. If you think those fancy fluvals are ugly then you haven't seen the things I filter with :lol:. Trust me I don't pick a filter over looks most the time. However cleaning a sponge does not significantly harm the bacteria on it.
Unless you have really long power outages or unstable tanks this issue is not a factor. Even the crappiest HOB filter should last 6 hours during a power outage with insignificant bacterial loss. A internal or canister will last longer. Also sponge filters can be run on powerheads too. IMO bacteria in our filter lasts a lot longer then you give it credit for. Vast majority of power outages are less then 8 hours in which case for most filters you don't have to do anything. Canisters require some labor to run after 8 hours, at which time you should start moving water through it. Very easy to do, just disconnect the output and as soon as you lower the hose below the water level you have a siphon. Just pull new water into canister and pour the stuff that comes out back into the tank. Do this for ten minuets or so ever 2 hours AFTER 8 hours have gone by.
Lastly I can just do away with the silly idea of a filter and just set my tanks up properly;-). Two of my tanks operate without any filter. One can go at least a week sitting stagnant(I intentionally left the filter off to see and one week of the tank being stagnant, nothing exciting happened:-?) This same tank is not filtered at least 6 hours of the day, since its noisy I turn it off when I go to sleep. I've never tested the big tank, would depend on alot of factors. It could go at least 24 hours stagnant. It holds all my breeding groups, so it always gets the most attention anyway.
I prefer plants, and when I don't have the option of having plants I might as well not have gravel. The issue with UGF and plants is if you want plants you actually want crap to build up in the gravel. Frequent cleaning it is the last thing you want to do. If you run a UFG in the original manner and over feed it would probably work. But a reverse flow wouldn't work as well for plants.
The benefits of every filter depends on the type of tank you want to run. You can not come straight out and say one filter has more benefits then the other. It doesn't work that way. Its like trying to say a minivan is better then a sportcar. To some it might be to others it might not. Depends what you want your filter to do.
tell me more please
4) Totally agree, but not a problem with pre-filtered, reverse-flow powerheads.
Tell me more about these reverse flow powerheads please? I have an undergravel filter in my 20 gal tall, and I have an outside filter as well.. I will continue to use both, but I am interested in what you mean by pre-filtered reverse flow powerheads..
Google "Penguin 660R powerhead". It is just a standard powerhead that comes with a kit that lets you send the discharge down the undergravel filter's tubes instead of pulling water up them. This completely changes how your undergravel works for the better. It comes with a small filter kit that goes over the intake to clean the water before it is sent down. Here is a link to the owner's manual: http://www.marineland.com/sites/Mari...nge_manual.pdf There is a good clear photo at the top of page 8 that shows a prefiltered reverse flow set-up.
There are other brands. This just happens to be the particular one I have. You can also buy just the reverse-flow "kit" if you already have a compatable powerhead.
Though I have had as many as 8 at a time, (I used to pay for my fish habit by raising and selling Africans to retailers), I now only keep one community "show" tank and I want lots of fish and plenty of "action". I plan to over-stock it a bit and therefore think I could use the extra biological benefits of the set-up I described. And since it is a show tank, I don't want a sponge filter in it. That's just me. But I admit I am not crazy about all the extra hardware in the tank to go reverse-flow either. Trade-offs, trade-offs.
I had never been part of an aquarium "community" like this forum and had no idea undergravel filters had become so controversial till reading comments here. Being an advocate of them, I felt the need to toot my horn a bit on the subject and let others know they do have some benefits and are still a viable option.
I have survived power outages of 2 days, 3 days, and 1 week. :shock: 12 hours is common around here. It gets old.
"Forever" is a relative term at my house. It means till the next move or Wifey's next furniture re-arrangement party. :lol: About 6 years tops. I should have clarified that.
I think this is a great article. I myself have been in the freshwater hobby for about 30 years now. I would take the conversation a step further and suggest that Undergravel Filters and Sponge Filters are virtually identical in their benefits.
At one time my fishroom had 34 freshwater aquariums, ranging in size from 2 gallons to 90 gallons, and every one of these was run by a sponge filter as the only source of biological filtration. The large majority did not have any other form of filtration. The key to keeping them from getting clogged and needing cleaning is very simple. You place the sponge filter under the gravel. Doing so allows you go to 6 months to a year between rinsing of the sponge.
The sponge has the same additional advantages to a u/g filter. First, they can be operated by a battery operated air pump. Second, they can be used in conjunction with a reverse flow powerhead, preventing clogging. And finally, you can easily move the sponge from one aquarium to another, eliminating valuable cycling time when needing an emergency filter in a hospital or quarantine tank.
I post here as support to the original article on undergravel filters. The biological benefits are very valuable. I personally stopped using undergravel filters and sponge filters when the Penguin Biowheel units hit the market. Dollar for dollar they are less expensive to purchase and easier to service, and provide outstanding biological benefits. However, the advancement of one technology does not reduce the effectiveness of another.
Well, undergravel filters remove a bit more suspended matter than UG's... This is only from reading, as I've never ran either one.
Before I decided plants, I was close to setting up an UG filter. If I set up a marine tank, I'll probably use one. :P
The only problem with UG filters and plants is that the UG filter prevents rooted plants from bringing in nutrients. Root tabs and enriched substrates would only cause a huge mess.
UG's are great for african lakes where you never want to use a plant, but I would imagine you can't just stop using the filter when you want. Wouldn't the bacteria in the substrate hurt the water?
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