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FAQs on Freshwater Undergravel Filtration

Related Articles: Undergravel Filtration, Freshwater Filtration, Setting up a Freshwater Aquarium, Tips for Beginners

Related FAQs:  Undergravel Filters, SW Use of Undergravel Filters, Freshwater Filtration, Biological Filtration, Establishing CyclingChemical Filtrants,

Can, do work... but require regular vacuuming to keep semi-clean.

Found on bottom side of UGF       8/25/15
Good Evening.
I am wondering if you might be able to help me identify what type of eggs these could be in my 150 gallon tank?
<Absolutely no idea! Need a bigger photo or a zoomed in view.>
I had been battling some kind of disease in my 10+ year old Oscar but lost our battle this past weekend...
<Not related, at least, not directly. However, if you have a lot of "stuff" growing in an aquarium, whether algae, snails, or unidentified life forms like these, it can indicate a lot of organic material in the tank. Review, and act accordingly because organic-rich aquaria are often associated with high nitrate levels, and this in turn seems closely linked to Hexamita and
HITH/HLLE infections.>
Most recently I treated her for Hole in the Head but at the same time it appeared like she could also have fungus/bacteria.
<Understood. HITH and HLLE are complex diseases. A parasitic protozoan called Hexamita may be involved, but the triggering factors are environmental (low oxygen, high nitrate) and dietary (lack of vitamins, especially those from vegetables). Oscars for example are omnivorous in the wild, consuming a lot of plant material, not necessarily directly, but
incidentally to their foraging, and without replicating this, and by feeding too much high protein food we end up with creating the triggers that lead to HITH and HLLE.>
Then, while cleaning the tank today, discovered these strings of eggs on the bottom side of the UGF but haven't had any successful IDs yet.
Anything you can direct me towards? Look familiar? Common treatments for a tank I hope to use again.?
<Almost certainly harmless. Certainly not disease-causing. Feel free to ignore or scrub away with hot water.>
I really do appreciate your time in advance.
Tina
<Most welcome. Cheers, Neale.>

Landscaping Fabric      8/6/15
I have some vague ideas of using polypropylene landscaping fabric (also called weed barrier) to control gravel movement above an UGF.
<Yes; this; and screen door material and more have been used for this purpose... and to make barriers for plenums>
It's fine enough that it could perhaps even keep sand in its place, and yet it passes water easily. I suppose the fabric would also become a bed for bacteria.
<A bit>
As long is it's just polypropylene without added chemicals, it should be safe for my tank, right?
<Yes>
Is there some obvious difficulty that I'm oblivious to?
<None really.... easy to cut w/ a utility knife or good scissors. Bob Fenner>
Re: Landscaping Fabric      8/6/15

Thank you.
I've enjoyed learning from WWM. Not only because it tells me things I don't know, but because of how I'm told:
Facts are generally substantiated, opinions are generally given as opinions, and new information seems welcome and accepted.
A rare treasure, in my experience.
<Ahh. BobF>

Reverse UGF system - with Cory's       8/26/14
Hi..and although not so particularity important, I have been successful in keeping cold water & tropical fish on/off for about 40 years. Within this time many things have changed regarding the general knowledge of keeping healthy fish/plants & maintaining aquariums. Efficient filtration is always been key to any successful aquarist. As a bit of show an tell ..& I’ve not always gotten it right...
<Indeed, I know the feeling!>
In the late 70’s used a UGF’s, then in the 80’s I ran the higher flow UGF’s & a HOB filter. In the 90’s I did the HOB Bio filter plus the hi-flow traditional UGF...with more empathise on Bio HOB than UGF......then I took a break to do other things...
It’s now 2014 & I have re-entered “pet keeping of fish” knowing a little of something. I now run (very efficient & expensive) canister filters ..which provide for a stable & sustained environment (Eheim 2217’s or 2215’s & a FX5’s on hi-flow tanks..plus simple bio-filters) depending on bio load...my water is always clean & clear.....super healthy. So why am looking at reverse UGF’s in 2014?
<Because they're really good filters?>
I’m not only into keeping aquariums, I’m into keeping efficient aquariums via better efficiently obtained by as low tech, solar power or using existing energy as able. Oh did I mention I’m cheap! I’m left wondering would it not be even more bio efficient to add a REVERSE flow UGF to the primary exit flow of a canister filter...rather than allowing the energy to be expended as O2 generation by surface turbulence.
<Absolutely correct. Reverse-flow is optimal in regard of keeping a well-oxygenated, clean bottom to the aquarium, something other filters don't do well, if at all.>
I have never had any issues with the traditional flow UGF ...I have always done water changes via a siphon of the UGF tubes..but I also did not keep bottom dwelling species such as Corys either with UGF’s. So.. will a reverse flow UGF mean that gravel level fish will be exposed to lesser quality water than mid or high level fish?
<Reverse. By pushing water thoroughly around the aquarium, from top to bottom, undergravel filters ensure uniformly good water quality and oxygenation. Adding the reverse flow element to the process further improves things by keeping the solid waste out of the gravel and forcing it towards the filter inlet, where it ends up in the sponges for easy removal.>
I run natural planted tanks & plan a layout of a reverse UGF tank, with the rear 25% of the tank as being a “potted tier”....dropping immediately to a 2” flat gravel.
<Could work, but obviously less effective than using the whole filter plate, and it may well be more solid muck accumulates on the planted area without suction because of this.>
So 75% of the tank will be flat (where the reverse UGF is placed..no plants). The idea is, that, where the fish swim, it will be managed by a clean strong reverse flow (Eheim 2215 exhaust).
<Could you not stick with floating and epiphytic plants instead? And make the whole substrate the undergravel filter plate? The variety of plants you'd have would still be substantial: Anubias species (there are several), Java fern, Java moss, Bolbitis are all epiphytes that are easy to get. Tie them to bogwood, place on the substrate, and they won't care less about the flow of water. Likewise floating Indian Fern, Amazon Frogbit and all the other floating plants add more options.>
The growth section afforded to rooted plants will be provided in the tiered section (25% rear of the tank) & managed by the canister. From a plant or general fish point of view ...I see this plan as a win/win. .BUT I keep a various clans of Corys & loaches (24+ combined) & before I migrate them to a new environment. I wish to seek any advice regarding if a reverse UGF system will cause them any harm. ....logically I can’t see that any harm can be caused, as filtered water will be passed via cleansed media....but I have had these fish for many years & would appreciate any advice on changing their filtration environment from a canister only environment to a reverse UGF/canister environment.
<The problem for bottom-feeders is switching from a sand/fine gravel substrate (optimal for the cats and loaches) through to medium grade gravel (optimal for undergravel filters). Adult Clown Loaches probably wouldn't care, but small Corydoras are likely to lose out and the risk is damage to their barbels as they try to burrow and find food. Non-burrowing bottom feeders like L-number catfish and Plecs will be fine though. Cheers, Neale.>

frog tank question; UG use, mod.        7/2/14
I have a ten gallon tank. About half will be earthy substrate, the other half will be water about 4-5 inches deep. They will be divided with a piece of acrylic. I was planning on using an undergravel filter to keep the water half clean in addition to doing occasional partial water changes, but am not sure about how to set this up with the divider in place.
Would it be possible to cut the filter plate so that it fits in just the half of the tank with the water? Or is this a bad idea? If so, do you have any other suggestions for setting this up? Thank you
<There is nothing wrong with cutting undergravel filter plates to size. However, water will always flow along the line of least resistance, so whatever you choose to do, you have to make sure the water HAS to flow through the gravel to get into the water pump, not around the edges of the filter plate. Consequently, for irregular sized aquaria, it is almost always easier to use a canister or air-powered sponge filter. Does depend on the types of frogs of course; Dwarf Frogs will likely be harmed by canisters, so air-powered is best for them. But bigger frogs like Xenopus are fine with moderate canisters. Cheers, Neale.>

Reverse UGF – 05/13/12
Good Morning,
<Hello Jill. Sorry we didn't answer this question sooner. Got put into the brackish mailbox marked as "read", so I didn't notice it was there.>
First I would like to add my thanks to you all for providing such a wonderfully informative site to the long list I have read so far and add that I believe I have become addicted to all the information available. My tank is a 45 US Gallon brackish tank spec gravity 1.004 @77F, ammonia 0, nitrite 0, nitrate 5ppm. I do not currently have a test for the hardness (have been unable to find on at the big box fish place) but intend to rectify that today.
<Wouldn't lose sleep over this. If you're adding marine aquarium salt mix, pH and hardness should take care of themselves.>
I have just discovered a not big chain LFS that has a more knowledge staff.
Currently I have 11 Dalmatian Mollies 3M:8F, I am planning to add all female swordtails to the mix to help control the Molly fry population and will look around for something else interesting and compatible. I currently have a UGF and a HOTB carbon filter which brings me to my question regarding the filtration system, would converting the UGF to reverse UGF using a canister system be beneficial to my tank or am I better off staying with the current set up?
<The benefits of a reverse-flow undergravel are two-fold. Firstly, they keep the water clearer (as opposed to simply clean, which refers to ammonia and nitrite). Because the upwards flow of water through the gravel pushes solid waste into the water column, it's easier for the canister filter to remove this solid waste. So you shouldn't get cloudy water or grubby gravel, assuming of course you clean the mechanical filter media (typically sponges or filter floss) in your canister. Secondly, they provide excellent ammonia and nitrite removal. You can clean the canister filter as often (and as thoroughly) as you want without worrying about killing bacteria, because there will always be lots of good bacteria in the gravel. Any down-sides to reverse-flow undergravel filters? Two of note. Firstly, they're essentially incompatible with plants, or at least plants with roots (they're fine with floating plants and epiphytes such as Java fern and Anubias). Secondly, they only work properly if the gravel bed is more or less flat and open. You can't cover much more than, say, 15% of the substrate with rocks, and if the gravel bed is particularly thin anywhere, the water will mostly go through that area of least resistance, by-passing most of the filter bed. But since you already use an undergravel, you'll be aware of these two limitations.>
Thank you for your advice,
Jill
<Glad to help. Cheers, Neale.> 
Re: Reverse UGF    5/16/12

Neale, Thanks so much for the information. So far everything has been working great with the UGF and I intend to hook the canister filter to it this weekend I have been looking online for any information but haven't had much luck. Am I on the right track in thinking the output hose should be attached to the UGF lift tube on the opposite end of the intake hose?
<Ideally, perhaps. But because the flow of water from the canister is pushed across the UG filter plate, there should be a reasonable flow of water all around the tank. Yes, it'll be weaker the further you go from the downward flow of water from the canister into the gravel, but in average-sized tanks this shouldn't be a big problem.>
What do I do with the second tube does it need to be blocked or is it ok to leave open with the air tube and pump disconnected?
<The second uplift on the undergravel plate? Yes, it needs to be blocked, or connected to either a powerhead (set to flow downwards) or a second canister filter.>
Thanks again for all the wonderful information, Jill
<Most welcome, Neale.>

55gal undergravel filter   7/6/11
Hi Crew!!
<Hiya Dan!!! Darrel here>
Alright... first off... I apologize for how dumb this first question sounds.
<Uh oh>
A school near me got a tank, and they want me to help set it up. I have experience with my own marine tanks (FOWLR mostly, some reef), but the new tank's gonna be a bit different I think. Anyway, it is a 55 gallon marine rectangle tank with undergravel filter. Not sure what lighting they got, it looks like average fish-only lights. But... here comes the dumb question... Can I use fine-grained live sand with an under gravel filter?
<Dan '¦ you think THAT is a dumb question?? Man '¦. DanTheMan '¦ you aren't even in the LEAGUE of dumb questions if THAT is your lead-in!!>
I have no experience with under gravel filters, and most of my tanks have DSBs with live sand, piles of live rock, etc. So, as I plan on stocking this tank with fish and a few odd invertebrates (think brittle stars, cleaning gastropods, etc.) I was wondering what your recommendations would be. Should I:
1. Use the undergravel filter with the gravel (I understand that this would mean fish only, not much live rock, etc.).
<Nope. Take the undergravel filter and return it to them and tell them to get their money back. Undergravel filters aren't suitable for any tank that can't (or won't) be broken down and cleaned on a regular basis>
2. Use it with fine/very fine sand (think sugar, maybe a little smaller).
<Answer #1 nullifies this question>3.
Remove/cap off the filter and make it like one of my own tanks (DSB, live rock, etc.)
<See? You were getting there on your own>
The reason I ask about the sand is because I am in the Marshall Islands, where a some of your guys' live sand actually comes from.
<Well, Dan .. here's the deal. *WE* use Live Sand from the Marshall Islands because it's an exotic, imported sand. *YOU* on the other hand, will be using crummy LOCAL sand>
Personally, I love live DSBs, but I'm not sure that would work with undergravel filters, as I've never worked with undergravel stuff before.
<Undergravel was a brilliant idea in CONCEPT but in practice it makes for a vast un aerated bed of decomposing detritus that can't be siphoned.>
Frequent water changes (i.e. your recommended 10-20%) will not be a problem.
<Well again, Dan .. are you going to use that crummy LOCAL water?? Or fancy Imported water from places like Des Moines, Iowa or Perth-Amboy, New Jersey?>
Thanks for your patience,
<Seriously. If you know what you're doing, do what you know. And if you DON'T know what you're doing '¦ come here and answer questions for WWM!!! LOL>
Dan

Gravel and Undergravel Filters, FW, Neale's go    2/1/11
Hello Crew,
I hope all I going well for you there. I have several questions, please.
I am fixing to make some modifications to my 75 gallon FW tank. First I am taking the sand bottom out and replacing it with gravel. I have used gravel before but this time decided to try the sand but all the detritus shows up too clearly on it.
<A turkey baster is good here. But also it's a reminder that your water circulation is probably not that good. If dirt accumulates on the sand, then you need more or better mechanical (i.e., silt-removing) filtration!>
The last time I used gravel It was recommended to me by a LFS to used 1 pound per gallon (75) so as to have a substantial surface for my "good" bacteria.
<For an undergravel filter the weight of the gravel isn't really that critical. Instead, concentrate on the depth. Assuming you use a medium-grade gravel, 8-10 cm/3-4 inches is correct.>
Right now I am relying on media in my power filter for that and have had no problem. Would it be OK for me to use less gravel so I won't have as much to clean?
<If you aren't using an undergravel filter, then you can have the gravel as thin a layer as you want. But if the undergravel filter is being used, you MUST have above 8 cm/3 inches for results to be worthwhile.>
Also, I have had tanks with and without under gravel filters and have read both pros and cons on their use. Please tell me what your feelings are about using them.
<Undergravels are great, and reverse-flow undergravels are superb because they "push" solid waste into the water where the canister filter can get it. But the chief drawbacks to undergravels are these: [A] You're limited to floating and epiphytic plants for the most part, because plants that are buried in the substrate rarely grow well. [B] You're limited in landscaping because the gravel MUST be more or less flat across the bottom of the tank, otherwise most of the water will go through the thinnest part of the gravel bed (water flows down the line of least resistance). [C] You can't have too many rocks or roots because anything below them is essentially dead so far as filtration goes. [D] You can't keep fish that dig too much otherwise the undergravel filter will be short-circuited. On the plus side, undergravels are quite easy to maintain except for cleaning under the gravel plate every 1-2 years; they are extremely efficient as biological filters; and they're very cheap to set up and run.>
Lastly, I want to get one of those in the tank background inserts that look like rock and fit against the back glass. Could you please recommend a particular brand that looks realistic as well as allowing for the intake tube on my power filter to hide behind it?
<They're all good, and once algae is grown on them a bit, they can look extremely realistic. Here in the UK, the Juwel brand is particularly popular. But there are some cautions. Firstly, you need to almost always cut them to size yourself unless they're pre-set for a particular aquarium model. Secondly, they need to be Siliconed in place at least 24 hours before you add water. Thirdly, Panaque spp. catfish (and perhaps some other big Loricariids) will scrape away the paint, revealing the epoxy or polystyrene behind the paint.>
Thank you for all you do. You are appreciated. James
<Thanks for the kind words. Cheers, Neale.>
Gravel and Undergravel Filters, ala RMF    2/1/11
Hello Crew,
I hope all I going well for you there. I have several questions, please.
I am fixing to make some modifications to my 75 gallon FW tank. First I am taking the sand bottom out and replacing it with gravel. I have used gravel before but this time decided to try the sand but all the detritus shows up too clearly on it. The last time I used gravel It was recommended to me by a LFS to used 1 pound per gallon (75) so as to have a substantial surface for my "good" bacteria.
<Mmm, yes... a couple/three inches... of depth... functionally, depending on grade et al. considerations. Read here:
http://wetwebmedia.com/FWSubWebIndex/fwsubstrates.htm
and the linked files above...>
Right now I am relying on media in my power filter for that and have had no problem. Would it be OK for me to use less gravel so I won't have as much to clean?
<Mmmm, yes, to extents>
Also, I have had tanks with and without under gravel filters and have read both pros and cons on their use. Please tell me what your feelings are about using them.
<All posted... do learn to/use the search tool, indices... For here:
http://wetwebmedia.com/FWSubWebIndex/fwugfiltr.htm
and the pertinent linked files above>
Lastly, I want to get one of those in the tank background inserts that look like rock and fit against the back glass. Could you please recommend a particular brand that looks realistic as well as allowing for the intake tube on my power filter to hide behind it?
<Oh! There are some really spiffy ones available (differentially) around the world. Rather than referring you to something you won't be able to secure, DO take a look on the major etailing petfish websites in the country you live in... U.S.: Dr.s Foster and Smith, Marine Depot... .coms>
Thank you for all you do. You are appreciated.
James
<Welcome. Bob Fenner>
Gravel and Undergravel Filters, Now James    2/1/11
Under Gravel Filtration / Artificial Background
Hello Crew, I hope all I going well for you there. I have several questions, please. I am fixing to make some modifications to my 75 gallon FW tank. First I am taking the sand bottom out and replacing it with gravel. I have used gravel before but this time decided to try the sand but all the detritus shows up too clearly on it. The last time I used gravel It was recommended to me by a LFS to used 1 pound per gallon (75) so
as to have a substantial surface for my "good" bacteria. Right now I am
relying on media in my power filter for that and have had no problem.
Would it be OK for me to use less gravel so I won't have as much to clean?
<The key to an under gravel filter is to keep the substrate even over the filter plates. Water takes the path of least resistance. It will go through the area with the least amount of substrate covering the plates. A pound per gallon has always been a standard for a very long time. If you plan on having fish that dig, like cichlids, then this filter may not be the best option.>
Also, I have had tanks with and without under gravel filters and have read both pros and cons on their use. Please tell me what your feelings are about using them.
< They were a very popular filter in the 60's and 70's, because they did indeed provide the biological filtration needed to break down toxic ammonia into nitrites and then nitrates. Then wet dry filters and Biowheel filters became popular and more efficient and the under gravels started to go away.
I keep cichlids so they tend to dig down to the filter plate making it useless.>
Lastly, I want to get one of those in the tank background inserts that look like rock and fit against the back glass. Could you please recommend a particular brand that looks realistic as well as allowing for the intake tube on my power filter to hide behind it?
< I have an artificial background on a 50 gallon tank It is both a blessing and a curse. They look beautiful. That is the plus side. Now the con. side.
Installation can be a nightmare. They will not fit an acrylic tank unless you do some modification to the top. You are limited on the size of a glass tank you can put them in. I found a heavy duty glass tank with no partition in the middle. Any bigger tank than a 50 gallon and you need to remove the center brace, install the background and then replace the center brace. They are usually made of a poly foam material that tends to float at first, so it needs to be anchored down. Once installed you see that it displaces from 1/4 to about 1/3 of the available aquarium space for fish. Now the 50 gallon is a 35 gallon tank. You can now place the heaters and the filters in the back but now you have another problem You need to pump the water from behind the background to the front of the background where the fish are. You can use a powerhead or a canister filter to do this. If the water doesn't flow around the sides or under the background you will need to cut some holes or slots to let the water get to the back of the background. You will then need to glue some screen over the holes to keep fish from getting behind the background. Now that it is all set up and running it will look great for awhile until it gets covered with algae. You will need some algae eating fish to get the algae under control. Razor blades and scrubbing pads may damage the background. Just get the background that you like the most.
Brands really don't matter as they are all the same. Hope this helps.>
Thank you for all you do. You are appreciated. James
< Thank you for you kind words.-Chuck>

Re: More re: Goldfish Filtration: Trickle or Canister (now reverse flow UG)   7/6/10
Neale, can you fill me in on reverse flow filtration? I am not familiar with that.
Thanks!
Catherine
<A reverse-flow undergravel filter uses the outflow from a canister filter to push water into a standard undergravel filter plate. Water rises from that plate through the gravel, and in doing so pushes solid waste into the water column where it is sucked into the canister filter. The result is that the gravel stays much cleaner than in any other type of aquarium because the gravel is constantly being cleaned. The gravel also works as a biological filter, ensuring excellent water quality. The downsides are these: Firstly, undergravel filters can't really be used with plants. The
exceptions are plants without roots, whether attached to bogwood or floating at the surface; either of those types of plants will grow fine.
The second limitation is that the gravel needs to be more or less uniform for best effect. Water flows along the line of least resistance, so if the gravel bed is shallower at one part of the tank, that's where all the water will flow. Obviously, if you dump big rocks on the gravel bed you'll be creating dead spots that won't work as a biological filter. Finally, you need an adapter to connect the outflow from the canister filter to the undergravel filter. Because of the limitations on plants and rocks, reverse-flow undergravel filters aren't widely used now that people like to
create natural-looking aquaria, but they remain good value filters for situations where large rocks and rooted plants aren't going to be used. If your Goldfish are being kept with a few plastic plants (or Java ferns, or floating plants) and some ceramic ornaments, a reverse-flow filter will work just fine. Cheers, Neale.>
Re: More re: Goldfish Filtration: Trickle or Canister, reverse flow UG   7/8/10

Neale, thanks very much for that explanation. I did not know you could do that. Keeping gravel clean in a goldfish tank is a real challenge, so I have stayed away from it--but I actually would like to have it. It seems that if this is set up properly, reverse filtration may be one way to manage it.
Regards,
Catherine
<Glad to help. Yes, a reverse-flow undergravel filter is a "tried and trusted" approach to keeping messy fish tanks clean. Well worth researching. Cheers, Neale.>

SW UG Filter question, 2/18/10
Hi, Folks.
<Hello>
I see that you are continuing the excellent job of helping people.
<Thanks>
I am planning a 90 gallon marine aquarium. Lots of thinking and reading to do, and the WWM site has been a tremendous help, as has a good re-reading of "The Conscientious Marine Aquarist".
<Great>
One question to which I do not seem to be able to answer, though, is whether it makes sense to include an undergravel filter in the system. I am planning to have the following in the system:
- overflow box to feed a sump
- sump with AquaC protein skimmer
- large canister filter
- 90 or so lbs. of live rock to initially cycle the system
- 20 or so lbs of live sand mixed with the normal stuff (~4" total) to initially cycle the tank.
<Sounds nice.>
I still need to figure out what else I need in the sump, but those are, I believe, the basics.
I still have a lot of reading to do on the WWM FAQ pages.
Is an undergravel filter redundant or a good idea in this setup?
<I would consider it unnecessary and a bit problematic since it will trap detritus is a difficult to clean place, I would skip it.>
This will start as a FO system and progress through FO with invertebrates and eventually a live reef system (but that will take a year or two, I suspect).
Cheers
Dave
<Good luck with the new tank.>
<Chris> 

Filtration and substrate upgrade  11/29/09
Hi, Neale
<Mark,>
I have 55 gallon tank on metal stand with 2 parrots hybrid (mated pair- 6 inch male and 3.5 inch female), 2 male (I think) Severums (7 inch each) and gibbiceps Pleco (11 inch). All fish live and grow together for almost 3 years.
My filtration is 2 hang on the back Aquaclear 50.
<Sounds fun.>
Soon, when my fish grow, I realize that my fish tank is very heavily stocked and my Aquaclear filters are doing nothing for mechanical filtration.
<Indeed; with "messy" fish, by far the best approach is to use a reverse-flow undergravel filter. This automatically lifts the gunk out of the gravel, into the water column, where the canister filter can get it.
Every other type of filter -- to some degree -- leaves the gunk in the gravel, and ultimately, this makes the water cloudy.>
I do ridiculously big water changes (60-70% weekly), but my water is becoming slightly cloudy next day after water change.
<Classic sign of insufficient mechanical filtration.>
My nitrite is always 0 and my nitrate, surprisingly, is never above 20 ppm (or at least I've never seen it is higher). But, sometimes, I can detect ammonia (0.25 ppm). This, probably, the reason for mild fin rot cases for my Severums (parrots and Pleco never were affected), which healed in few weeks, after I did big water changes and stopped feeding.
<It's very likely your overall mix of filtration isn't adequate. Get rid of stuff you don't need -- carbon and Zeolite for example -- and beef up the mechanical and biological media.>
I decided to add third!!! filter (Eheim 2215) to improve mechanical filtration.
<Cool.>
Do you think, adding Eheim canister filter, will improve my water quality and clarity? Will I still see bunch of fish waste floating around the tank?
<If you make the slightly more complicated stage of adding an undergravel filter, yes, it should help significantly. On its own, a canister will help, but proportional to its "suck" -- the more circulation, the more gunk it'll remove from the water. This is a less efficient approach to a reverse-flow undergravel, but it can work.>
In order to install this filter, I need to replace aquarium stand: instead of metal, I'll put wooden stand to have place to put Eheim filter. So I need to reset my aquarium completely.
<I see.>
This means, I have a good opportunity to change a substrate from gravel to sand.
<If that's what you want.>
I know, Neale, you are a big fan of the sand as a substrate, but do you really think it is worth to try for this kind of big and messy fish?
<In this instance, wouldn't be instinctive choice. A reverse-flow undergravel with an inch or so plain gravel will be much cleaner. Sand is excellent, and keeps itself fairly clean in the sense gunk can't sink into it, but at the same time it doesn't make it any easier for the canister (or hang-on-the-back) filter to keep the water clean.>
Why you are using mixture of sand and gravel in your tank?
<I use a mix of sand and gravel simply for its look. It's a nice combo.>
Overall, in your opinion, is it possible to keep these fishes healthy in 55 gallon for life?
<It's borderline, to be honest. 55 US gallons is 210 litres, slightly more than my 180 litre "big" tank here next to me. That tank contains a variety of fish in the 5-10 cm (2-4 inch) size range but including one 15 cm (6 inch) Panaque Suckermouth catfish. It's clean and usually algae free, but that's with an Eheim 2217 and a Fluval 104, a total of about 1500 litres/hour, or a turnover 8 times the volume per hour. For me, this is the sort of aquarium size and filtration rate needed for a mix of predatory and messy fish. Now, I may be going for overkill here, but I'm simply making the point that a big, well-filtered tank is the one most likely to be algae-free and with clear, clean water. The more you step away from the ideal, the bigger the management problems become. There's a difference between a safe tank -- one with zero ammonia and nitrite -- and an easy tank -- one that gets by fine with occasional water changes and stays clean in between. So, 55 gallons may well be viable, but it wouldn't be my recommendation. If you get a good offer on a 75 or 100 gallon tank, jump at it!>
Thank you for your time.
Mark
<Happy to help. Cheers, Neale.>

Re: Filtration and substrate upgrade  11/29/09
Neale,
<Mark,>
Thank you very much for quick response.
I actually never used UGF before, and I did quick search and found that it is not recommended to use UGF with extensive diggers. I believe, parrots are a good example of the fish that like to dig. Is it safe to use UGF with
parrots?
<Indeed, I didn't comment on that. A plain vanilla undergravel will indeed be short-circuited by fish that dig. Parrots aren't especially bad, compared with, say, Oscars, but they do dig. The solution is simply. You lay an inch or so of the substrate on top of the undergravel plate, then lay something called a gravel tidy, and then scatter a thin layer of gravel on top. The fish can dig as much as they want without getting through the gravel tidy. You can buy ready made gravel tidies, but I'm cheap, so I use pond-safe plastic mesh from a garden centre. Costs very little. Cut to size with scissors, and off you go. Choose a mesh small enough to stop gravel falling through, and strong enough to hold its shape, but not so fine it'll slow down the flow of water. Something about the grade of a colander like
you'd have in the kitchen should be fine. Note we're talking about reverse-flow undergravels here, not standard undergravels, which *such* gunk into themselves. Reverse-flow UGs do the opposite, so are essentially self-cleaning, almost like Jacuzzi in keeping the water circulating upwards.>
Thanks,
Mark
<Cheers, Neale.>

Bubbles coming from nowhere out of my under gravel filter. 5/8/09
<Hi Scott>
I have only today discovered your site, although now that I know about it I will be back often.
<Great.>
I have learned a lot of great stuff in searching for the answer to my question, but have not found the answer itself.
I have a 600 L marine/reef tank which I run under gravel filters in. (one type among several filters) The tank is nearly 2 meters across and the under gravel filters are split into two systems, left and right, which are not
interconnected. Each side is powered by a 2000 l/hr power head, pulling the tank water through the gravel, into the PVC lattice under the gravel, and then returning it to the tank. No air is added to the filter, the power head is positioned just above the level of the gravel (about .6 meter from the water surface) and should only ever see water being that it's operation is all in the bottom 6 inches of a pretty deep tank.
The mystery for me is that every 5 to 10 minutes a blast of fine bubbles is blown from the power head on the left under gravel filter. I am totally stumped as to where these bubbles are coming from??!! My tank is nearly 6 years old and I have not seen this before. The bubbles just appeared one day about 2 months ago at 1 to 2 hour intervals, and over the last few months the interval between the bubble blast has become shorter and shorter. I
don't imagine any problem for the critters in my reef, but not understanding where the bubbles are coming from is driving me mad.
Thanks in advance for your expertise!
<Doesn't sound good Scott. I believe your bubbles are hydrogen sulphide gas, a common problem with undergravel filter systems that have been in use for an extended period of time and needs to be addressed quickly. I would do a water change using a gravel cleaner type siphon.
Start with the affected filter, and do this with every future water change. Is a prime requirement in maintaining these
type of filters.
Do read here and related articles/FAQ's
http://www.wetwebmedia.com/fwsubwebindex/ug5proscons.htm
James (Salty Dog)>
Scott Garner

Question on Building UGF System (RMF, opinion?)  12/16/08 Back in the mid 80's I built a 110 glass saltwater tank. I had triggers. The tank had a cracked bottom when I bought it from the fish store. They had the bottom replaced and drilled with three outlets. I built a UGF system with egg crate and covered it with screen and two returns at the top of the tank. I used two Magnum 330's. Are systems like this still used? I had my tank for two years and I never had any problems. A move forced me to sell. Regards, Jim B <Hello Jim. There is nothing intrinsically wrong with undergravel filtration. The reason you don't see such systems used much in either marine or freshwater fishkeeping is that the alternatives are less expensive than they were, and at least some of these alternatives offer very real advantages. In the case of marine fishkeeping for example, the use of live rock allows the complete nitrogen cycle from ammonia to nitrogen gas to be accommodated, not just the part of the cycle from ammonia to nitrate. Hence marine aquaria filtered with live rock enjoy better water quality (i.e., lower nitrate levels) than aquaria that are filtered using old school methods such as undergravel filters. On the freshwater side of things, undergravel filters turned out to be incompatible with aquatic plants because the presence of oxygen in the substrate made it less easy for plants to absorb the mineral nutrients they need. So aquarists with an interest in planting their tanks prefer to use canister filters of some type instead. Undergravel filters lose capacity in situations where there are lots of rocks (or corals) creating "dead spots", and fish that do masses of digging (for example cichlids or gobies) are liable to "short circuit" the system by creating channels through which the water can flow, by-passing the bulk of the filter bed. This isn't to say undergravels are redundant by any means. In the right tanks, they remain extremely cost effective. When used in the reverse-flow configuration are particularly well suited to tanks with large, messy fish where the separation of mechanical filtration (in the canister filter) from the biological filter (the gravel or coral sand substrate) makes maintenance much easier than would otherwise be the case. In tanks where the substrate will be expected to provide water chemistry control as well (such as a low-tech marine or Rift Valley cichlid aquaria) the undergravel filter ensures the water constantly passes through the calcareous substrate. In other words, while there certainly are better filtration systems available, there's nothing actually bad about undergravel filters, provided you understand their limitations and why many hobbyists have switched to the other filter types. Cheers, Neale.> <<Are still used... widely. And Neale's response is stellar... instructive, clear, complete... as usual. RMF>>

Converting to a planted tank - shutting off the under gravel filter 9/13/08
so i have this 55 gallon tank that I've been given charge of. it's been going for about 7 years. no plants, weak light. I'm putting in our budget next year money to up grade the lighting and put some plants in (and some more fish whee).
<Okay. If you're serious about plants, do spend the $ (or £, or whatever) on a good aquarium plants book -- money well spent. While lots of plants look similar, some do better in certain types of tank than others, and knowing which species to order online if your pet store doesn't have them makes a huge difference.>>
I've been reading all over on how to do a planted tank right, but converting a non planted to planted with my substrate I'm still not sure on. i currently have what i suppose could be called "generic aquarium gravel" in there. the pieces being .2 to 1 cm in size i guess. and an under gravel filter going on.
<The substrate will need an upgrade of some sort, perhaps the addition of aquarium/pond soil or some laterite.>
i understand a finer substrate is in order for a planted aquarium. but then, i don't exactly want to redo the entire eco system...so my thinking is that i will take about half the current gravel out and replace with something finer, probably some made for plants branded substrate on top of what i have now and let it over time mix up. Ok?
<Here's my advice for cheap and effective plant growth. Grab a bag of pond soil. It's sometimes called "aquatic soil" and you can get it at garden centres. It's essentially nitrate-free soil. The lack of nitrate means the water won't become polluted and your tank won't be overrun with algae. But being soil, it has lots of iron, copper, and all the other things plants like. Here's in England it's very cheap, a mere fraction the cost of Eco substrates, and easily 90% as good. If I recall, a 20 kilo bag (around 40 lb) costs under £5 (about $8). Put a 2-4 cm/1-1.5 inch layer of this into the bottom of the tank, and mix with some silica sand (again, "smooth silica sand" is widely sold in garden centres and costs even less than the soil). Fine pea gravel works just as well as sand, so choose whichever you like. Put a gravel tidy on top of this to keep it all in place, and then cover with gravel or silica sand as preferred. With the gravel tidy in place the fish can't expose the soil and make a mess, but the plants will send their roots into the stuff quite happily. It's a bit messy when you set the tank up, but after the filter is running a few days the tank will be spotless. Add your plants whenever you want, and off you go. A great aquatic plant substrate on a shoe-string budget! Works for me!>
The real worry i have and my question is this undergravel filter. what happens when i shut it off?
<Nothing much. The bacteria will die off course, but that's no big deal. Remove the gravel and the UG filter plate, clean up any nastiness (there won't be much, honestly) and then add your soil/sand mix on top.>
I'm not wanting to dig into the nasty underneath it and pull it out. I hope just to pull out the upshoot tubes and leave the thing in there.
<I wouldn't do this for lots of reasons. The main is that a dead "pocket" of water is not what you want in an aquarium. It's also a waste of space. Just pull the darn thing out... you're going to have to do this anyway for the plants.>
My hope is that all the detritus that's been sucked down inside it and to the bottom level of the gravel will just wait and become nutrients for the plants once the roots get down that far. But that will take some time.
<No, doesn't work that way. Trust me on this: you're saving ten minutes of work, but creating a huge disappointment in terms of how your plants will prosper. Plants need very specific things to thrive. Do also remember the alternatives: floating plants and epiphytes (species that grow attached to wood) don't need a substrate, and are JUST FINE with undergravel filters. You can create an amazing tank using just those kinds of plants. Anubias, Java fern, Bolbitis fern, Java moss, Riccia, Salvinia, Ceratopteris, Limnobium... just a few plants that would work in this kind of tank. Floating plants have roots that grow downwards, and epiphytes can be positioned at any level you want. With some care, you can create stunning displays with plants at every level.>
what do i have to worry about for the water of the aquarium when that stuff in the under gravel filter gets used to not having water pass through it?
<Don't do it this way. Not worth it. Cheers, Neale.>

Confused about UGF statement from crew   4/27/07 Thanks WWM crew for all you do for passing the knowledge forward. I recently (1 year ago) returned to the salt water portion of the hobby after being out of it for 20 years and have learned and re-learned many things and what a change from the late seventies early eighties. I have had freshwater tanks since the late sixties and was a little confused by a reply to a question asked by someone as I was reading over the FAQ's tonight regarding under gravel filters for FW tanks............. UGF and Power Heads, FW  - 04/25/07 To whom it may concern: Hello, <<Hello. Tom here.>> I have a 10 gallon tank with 2 separate filters and 3 goldfishes. I get a little frustrated with changing the filters every 2-3 weeks, so I purchased a UGF and a power head from aqua-tech. Did I made a good decision? I would really appreciate a straight answer. <<Straight answer? No, you didn't make the best of decisions here. First, I would rather have seen you place the money you spent toward a much larger aquarium. You're way overloaded where stocking is concerned. (Goldfish need far larger quarters to live in than most people believe or understand.) Specific to your question, though, a UGF requires a higher, not lower, level of maintenance than hang-on or submersible filters. If you're frustrated with cleaning your present filters every two to three weeks, you're not going to be happy pulling your UGF plates just as often to make sure they're clean and performing properly. It's because other styles of filters were designed to be more easily maintained that UGF's lost their popularity. They used to be the 'only game in town' in the past. Now, by most standards, they're simply not worth the effort. (For just a little 'sugar coating', UGF's work very well. Many hobbyists just didn't want to take the time to maintain them properly and this caused problems up to, and including, the deaths of their livestock.)>> thank you <<You're welcome. Tom>> Maybe I have been doing things wrong for 20+ years but when I look under my plates from the bottom of the tank (one with power heads running) I do see a small amount of build up but nothing to stress me or the fish about. <Mmm, well... circumstances result in highly variable experience here... but if one uses "almost entirely nutritious" foods (so that there is not much "left over" (think of spacemen/women in their space suits here...) AND there is no shortage of alkaline reserve (the mechanisms of decomposition here result in lowered pH, dissolved oxygen...) and a few other factors, then UG filters can be quite maintenance free... In actual practice though, more gravel vacuuming is required... along with disruption of the livestock, system... with UG use (Am still a fan myself)> I have never had to "pull my UGF plates up every 2-3 weeks" to clean them. The only time I have done this was when either moving a tank or breaking one down. I do not want to wreak havoc on my cycle. <Agreed> I run power heads in the lift tubes (smaller tanks have air pumps and stones) and when I do need to clean the build up under the plates I do not remove them but either run a hose down the lift tube to siphon or attach tube to the power head to suck out or by simple lifting up and down slightly where the tube meets the plate with power head running (if worried about clouding the water you could do it while changing water with hose attached to exit of power head to keep silt from entering tank water) to loosen  and clean out the deposits under the UGF. Of course I vacuum (alternating half one water change then the other the next time) the gravel to remove the mulm built up in it but never have I removed the plates just to clean. <Well-stated and a good practice> However the hang on filter does require more regular maintenance in my opinion for changing out the medium used there as the waste build up increases the nitrate and reduces water flow through the filter. Thank you, John Maggio <Thank you for sharing, sending along this well-written counter-point. Bob Fenner>

Re: UGs   4/27/07 Hello Tom, Bob, <Neale, Tom> I came across this message in the Inbox and wasn't sure how to respond to it, so am open to advice. <Good attitude> On the one hand, I have never found undergravel filters to be difficult to maintain. Yes, they need cleaning once a year and a good rake through once a month, but that's about it. They have numerous drawbacks I grant, but maintenance isn't really one of them. For their cost, undergravels can provide very good water quality. On the other hand, I wouldn't like to criticize the advice offered by another contributor. I also think Tom's basic comment that the tank is too small and an undergravel too pokey for goldfish is correct. I   personally don't consider goldfish suitable for anything other than very large aquaria, but that's just me. <We are in agreement here... I have posted a couple of articles I'd penned on these venerable filters... Do have some place still... but not with goldfish systems, other arenas where sped up reduction can be problematical> The message is in my mailbox folder if anyone wants to have a pass at it. <I'll have a go... and send all to Tom's in-folder as well. Cheers, BobF> Cheers, Neale > Thanks WWM crew for all you do for passing the knowledge forward. I recently (1 year ago) returned to the salt water portion of the hobby after being out of it for 20 years and have learned and re- learned many things and what a change from the late seventies early eighties. I have had freshwater tanks since the late sixties and was a little confused by a reply to a question asked by someone as I was reading over the FAQ's tonight regarding under gravel filters  for FW tanks............. >> UGF and Power Heads, FW  - 04/25/07 >> To whom it may concern: >> Hello, >> <<Hello. Tom here.>> >> I have a 10 gallon tank with 2 separate filters and 3 goldfishes.   >> I get a little frustrated with changing the filters every 2-3 weeks, so I purchased a UGF and a power head from aqua-tech. Did I made a good decision? I would really appreciate a straight answer. >> <<Straight answer? No, you didn't make the best of decisions here.   >> First, I would rather have seen you place the money you spent toward a much larger aquarium. You're way overloaded where stocking is concerned. (Goldfish need far larger quarters to live in than most people believe or understand.) Specific to your question, though, a UGF requires a higher, not lower, level of maintenance than hang-on or submersible filters. If you're frustrated with cleaning your present filters every two to three weeks, you're not going to be happy pulling your UGF plates just as often to make sure they're clean and performing properly. It's because other styles of filters were designed to be more easily maintained that UGF's lost their popularity. They used to be the 'only game in town' in the past. Now, by most standards, they're simply not worth the effort. (For just a little 'sugar coating', UGF's work very well. Many hobbyists just didn't want to take the time to maintain them properly and this caused problems up to, and  including, the deaths of their livestock.)>> >> thank you >> <<You're welcome. Tom>> > Maybe I have been doing things wrong for 20+ years but when I look under my plates from the bottom of the tank (one with power heads running) I do see a small amount of build up but nothing to stress me or the fish about. > I have never had to "pull my UGF plates up every 2-3 weeks" to  clean them. The only time I have done this was when either moving a tank or breaking one down. I do not want to wreak havoc on my cycle. > I run power heads in the lift tubes (smaller tanks have air pumps and stones) and when I do need to clean the build up under the  plates I do not remove them but either run a hose down the lift tube to siphon or attach tube to the power head to suck out or by simple lifting up and down slightly where the tube meets the plate with power head running (if worried about clouding the water you could do it while changing water with hose attached to exit of power head to keep silt from entering tank water) to loosen  and clean out the deposits under the UGF. > Of course I vacuum (alternating half one water change then the other the next time) the gravel to remove the mulm built up in it but never have I removed the plates just to clean. > However the hang on filter does require more regular maintenance in my opinion for changing out the medium used there as the waste build up increases the nitrate and reduces water flow through the filter. > Thank you, > John Maggio

UGF and Power Heads, FW  - 04/25/07 To whom it may concern: Hello, <<Hello. Tom here.>> I have a 10 gallon tank with 2 separate filters and 3 goldfishes. I get a little frustrated with changing the filters every 2-3 weeks, so I purchased a UGF and a power head from aqua-tech. Did I made a good decision? I would really appreciate a straight answer. <<Straight answer? No, you didn't make the best of decisions here. First, I would rather have seen you place the money you spent toward a much larger aquarium. You're way overloaded where stocking is concerned. (Goldfish need far larger quarters to live in than most people believe or understand.) Specific to your question, though, a UGF requires a higher, not lower, level of maintenance than hang-on or submersible filters. If you're frustrated with cleaning your present filters every two to three weeks, you're not going to be happy pulling your UGF plates just as often to make sure they're clean and performing properly. It's because other styles of filters were designed to be more easily maintained that UGF's lost their popularity. They used to be the 'only game in town' in the past. Now, by most standards, they're simply not worth the effort. (For just a little 'sugar coating', UGF's work very well. Many hobbyists just didn't want to take the time to maintain them properly and this caused problems up to, and including, the deaths of their livestock.)>> thank you <<You're welcome. Tom>>

Aquatic Edge undergravel filters   3/7/07 I was just recently given a fish tank. Well as with anything, it needed to be assembled.  I would like to know if there are any diagrams that show how to assemble the water filter, pump, and aquatic edge undergravel  filters. <I am not familiar with this product, but I was able to find a picture of what it should look like when assembled here, http://www.fish.com/itemdy00.asp?T1=701012+005.  Hope this is of help to you,  Brandon.>   Thanks

Switching from Under Gravel Filters To Other Filtration Methods - 02/11/2007 Hi WWM Crew, <<Hello, Glenn. Tom here.>> I hope you all are doing well today. <<And you as well.>> A few years back y'all helped me plan for changing my saltwater tank from UGF filtration to LR/DSB and sump/refugium. I made the change in 2004 and Nitrates have been undetectable since then. <<Can't argue with success, Glenn. Good job.>> I have a small 30L Malawi Cichlid tank that has been running for 7 years. I've always used UGF and the same gravel. After reading about some of the problems that a poorly maintained ( i.e. lack of regular water changes and substrate vacuuming) UGF system may develop, I've decided to switch to a power filter. <<Nothing wrong with making the switch, Glenn. I'd say that a tank running a UGF filter for seven years isn't at all bad but, I wouldn't disagree with the decision you've made.>> My plan is to run the UGF and new Power filter together for a period of time, then remove the gravel, UGF plates and vacuum out the bottom of the tank. Rinse the grave in tank water and add several inches back into the tank.  Of course the fish will be moved to a 30G Rubbermaid tub while I remove the filter. <<A suggestion? If possible, pull the plates without pulling out the gravel. Easier said than done, I know. Will very likely stir up a lot of gunk from the bottom but I'd rather not see so much of the beneficial bacteria potentially compromised. When all has settled out, a few 'deep' (all the way to the bottom) gravel cleanings will put your substrate back in good order. This will become the order of the day, anyhow. As I say, just a suggestion.>> My first question is how long should I run the Power and UGF filter together before removing the UGF? <<This one somewhat goes back to my last point. A couple of weeks should be more than sufficient provided the whole bacterial 'farm' hasn't been badly disrupted or disturbed. The media will seed with beneficial bacteria quickly in a cycled tank such as yours so I see no reason to run both together longer than this.>> The second is, how deep can I make the substrate? I know in marine systems, a SSB should be <= 1". Does this apply to fresh water as well? <<This one depends on the type/size of the substrate being used, Glenn. The finer the substrate, the shallower the depth should be. I'm running about 1' of fine, natural gravel in one of my tanks and about 2.5'-3' of coarser gravel in another. The key is to prevent pockets of build-up from forming away from the oxygenated region of the tank. No hard and fast rules here other than good common sense, really.>> Thanks, Glenn <<No problem at all, Glenn. Good luck with the change-over. Tom>>

Deep Sand Bed for Fresh water aquarium.   11/8/06 Hi Guys, <Oooh, what about the XXs?> I am new to this site but I used to keep marines - then I got married, had kids, got a proper job - pretty much in that order... <Let's see... in the not so wild west, "First comes... then comes familiarity...> Now I return, but have decided to keep Malawi Cichlids (Haps and Peacocks). <I keep these... and Mbuna in another system> I am still researching the species and bringing myself up to date with latest filtration techniques etc. I am space limited and so I know that the size of the tank is fixed at around 90G. I am interested in using a sump - for various reasons, but it has a lot to do with requiring a low maintenance, stable system because I am away from home 4 days a week. (That's what a proper job does to you). I am interested in incorporating a NNR refugium type compartment in the sump, and have read around the subject a little. However, I have a couple of really basic questions that I can't find answers for. This is why I write. My first question is how do they work? <Mmm, NNRs? Basically they harbour, foster anaerobic microbe populations... mild circulation delivers system water to the hypoxic bed, and chemical substrate (e.g. Nitrates) that are reduced (as in Reduction/Oxidation) to component molecules> Ha! Don't get upset. 6 inches of sand directly on the bottom of the tank with no forced water flow through it leaves me confused. How is the water that had nitrates removed replaced? How does water exchange work in the filter bed? <Is the same water... recirculated with/through the system en toto... and the water exchange is purposely very slow, gradual to keep oxygen tension low> My second question is this. If I set it up with a plenum, an uplift tube and a very low flow rate (say a few gallon per hour) will the efficiency of the sand bed be increased or destroyed? <This depends on still other factors/circumstances of how much substrate, its "grade", chemical/physical make-up... slow as you go is the route to go here... no uplift tubes, the "holes" for these plugged... No aided circulation through the bed other than simple diffusion, Brownian motion> (This is of course just a UGF with a low flow rate). When I was keeping marines the accepted wisdom at the time was that aerobic processes occurred in only the top inch and a half of substrate. Therefore it seems to me that with a deep sand filter some forced water movement could be acceptable without dragging oxygen too far into the bed. <Ah, yes... I remember those days/years> In any case it could be possible to increase the depth of the sand to compensate. <Yes, to some/an extent> I should add that the reason I am tempted to do this is again due to lack of space. The entire sump needs to be 80LX40WX40Dcm max. Any help you can offer would be very welcome. Thanks, Tony Baxter <The same rationale, design, operation... of such filtration, filters as per marine... Please use the search tool and/or indices on WWM to read about Plenums, DSBs for marine/SW set-ups... http://www.wetwebmedia.com/deepsandbeds.htm http://wetwebmedia.com/Plenums.htm and the linked files above... and apply this to your application. Bob Fenner>

Undergravel Fish?  11/7/06 Hello, <Hi Mark, Pufferpunk here>   I have this problem with my Flowerhorn fry.  They seem to always try to get under the gravel.  A lot of them are not getting back out. I want to try to vacuum the gravel but afraid that I might crush the fry while doing it. So, is this a big problem or the fry should be able to get themselves out? Please, need help fast--don't know if they can survive that long under the gravel. <Are you speaking of below the undergravel filter plate?  I can't imagine anything else you might be referring to, unless your gravel size is huge & they are being caught between the pieces.  If you are referring to the undergravel filter plate, the same thing happened to my Cory catfish fry.  I took the down tube out & lifted the plate by the hole slowly, letting the gravel drop to the side.  All the fry were fine after that.  Please correct me if my assumption is wrong & describe the problem better.  Also, it would be good for the fry to have some fine-leaved plants (live or fake) to hide out in.  ~PP> Thank you very much, Mark

Removing an UGF  8/24/06 Good morning! <Hi Nicole, Pufferpunk here> I have a 29 gallon community tank filtered by a Penguin 150. I had a powerhead connected to an UGF. I decided to try making use of an extra powerhead by connecting it to a Quick Filter (Hagen). I had it running since Thursday and at first was very excited as it polished the water until it was sparkling!  The trouble started when I removed the other powerhead off of its lift tube for cleaning....suddenly I heard a pop and I realized I had removed the whole lift tube right off of the filter plate! I considered for a moment what to do, and ended up just throwing away the lift tube and covering up the exposed bit of plate with gravel.  Can I safely do this? Just abandon the undergravel filter and leave it as a large plate sitting uselessly under the gravel? Or do I have to remove the UGF completely? <I really don't like UGFs in general.  It seems like "sweeping dirt under the rug".  Unless used as reverse flow.  Here is an article that will tell you everything you need to know: http://www.thepufferforum.com/articles/water/ugfilters.html > I changed one of the two carbon filters (I change them alternately to reduce bio-filtration stress) and removed the power sponge filter, which had become darkly discolored - probably because of stirring up the muck beneath the filter plate. The package says you can leave it in for up to two weeks without changing the filter, I went ahead and changed it. From now on I am going to only run it on weekends, since it seems better for spot cleaning than continuous use. <I have completely removed UGF plates (my Corys had spawned & all the babies were underneath!).  It was quite simple.  I just grabbed onto the hole & pulled slowly up to one side.  The gravel just slid off.  I did a good stir & an 80% water change.> The water doesn't look cloudy per se but it does have lots of  small suspended particles in it, which haven't cleared up since the "incident" with the lift tube. I am writing because I fear discontinuing the UGF suddenly and removing the extra powerhead might have been a major mistake/disaster and I don't even know it! Although the fish seem to be acting normally in every way..  I will do whatever is necessary. <I prefer a good HOB filter like the Aquaclear for a tank like that (sorry, I'm not familiar with Penguins).  Using one & removing the UGF, shouldn't change your biological filtration much, as your tank seems well established.  I like to put 1" filter floss between the sponge & BioMax that comes with the AC filters (carbon is pretty much useless on a freshwater tank), to "polish" my water crystal clear.  ~PP> Thank you very much for your help! Nicole

Goldfish shut off the undergravel filter? Eats shoots and leaves...  7/14/06 Hello, <<Hi. Tom with you.>> I read on your web site that undergravel filters are not recommended for goldfish. <<Goldfish in particular because of their "messiness" but the recommendation holds for other species as well. I, and others, have addressed this one before but it may bear repeating. We don't recommend against this style of filter because it doesn't work. They can/do work quite well, in fact. The two primary causes for concern, however, is that these MUST cover the entire bottom of the tank and they MUST be maintained properly. When the first admonition is ignored or misapplied, pockets of detritus/mulm can build up in the "unfiltered" areas leading to potentially toxic levels of nitrates in the tank. Also, when not properly maintained, the same situation may arise should the filter plate(s) become clogged and left untended. This one may sound like a case of "pilot error" rather than the fault of the filter and, while we wouldn't argue that point, there are just too many good alternatives available to aquarists to justify the use of a style of filter that has led to a great many problems including otherwise "mysterious" deaths of livestock.>> I have a 46 gallon tank with 2 medium Orandas and 1 Ryukin. Currently I have an undergravel filter and a TetraTec PF500 power filter. I am considering shutting the undergravel filter off. I have a hot magnum filter that I could use to clean the gravel with prior to shut down and then reload with carbon to assist filtration during the transition. Do you have any advice or feedback? <<Your plan sounds fine and will eliminate potential problems down the road. Why run the risk?>> Thanks! <<Any time. Tom>>


Bowfronts and filtration  5/18/06 Dear crew: <<Hi, Jasen. Tom here.>> I have a bowfront aquarium and a problem. <<One of mine is a "bowfront", too, so let's see if we can solve the problem.>> I was told that since the tank isn't rectangular I can't use an undergravel filter with it. <<In a nutshell, UGF's are problematic because the can create problems with trapped particulate matter leading to high toxin levels. The general rule, nowadays, is to avoid them.>> Is this true? <<Yes. The trouble here is that a UGF should filter the "entire" bottom surface of the tank to eliminate "pockets" of collected detritus/mulm. With a bowfront tank, this isn't possible with a straight-line UGF. A matter of "geometry". The "bow" in the front of your tank will leave a rather large area for unfortunate build-up. Not a good situation at all.>> From, a fish lover <<From a fish lover, as well. Tom>>

Re: Bowfronts and filtration ... FW maint./op.     5/24/06 <<Tom here, Jasen.>> Thanks for your answer! <<No problem whatsoever.>> A couple more questions (and this time, could you return the answer to this email: XXXX). <<Should work, Jasen. Our replies of the typical e-mail variety so they go back to the address the questions were posted from. Looks like yours fits the bill.>> What is the main reason that aquarium water starts to smell, kind of like stagnant water?  Is that because of excess food on the bottom that rots? Or is it because of some kind of bad bacteria? What is the smell, ammonia? <<In a nutshell, all of the examples you've cited will contribute to the bad smell. Toss in some fish poop and you've got quite a smelly combination at work, most of it decaying/rotting and, generally, fouling up the place. As to the ammonia, it's possible that you might detect this but you'd have to have a pretty sensitive nose. Given that the toxicity levels that will kill fish is so low in "normal people" terms, it's a good bet that you'd have dead/dying fish on your hands if you could smell the ammonia.>> Also, what kind of fish can keep that problem to a minimum?  Catfish on the bottom? If so, what kind of catfish consumes old food on the bottom of the aquarium best? I know that there are some that don't eat the old food. <<To give you a serious but, seemingly, silly answer, small fish invariably result in a "cleaner" tank for fairly obvious reasons. They don't eat as much as large fish and, consequently, don't urinate/defecate as much. Less uneaten food - assuming they're fed responsibly - and less detritus. Catfish are scavengers, for the most part. I've, personally, got Corydoras and these guys forage non-stop. They'll do it regardless however, I wouldn't think of leaving them to live on what's "left over" from my other fish. Mine are fed sinking types of food, i.e. pellets and wafers, and I'd suggest the same to everyone else.>> Would it be better to have snails instead of catfish, or should I have both? And what about those kind of fish that seem to have their mouths glued to the glass all the time...I don't know what they are called, but I've seen them. <<Some snails can, and will, happily feed on old food and detritus. I'm not a fan of the little buggers but they do, indeed, prove useful in this respect. In stocking my tanks, Jasen, I get the type of fish that I like before I concern myself with what they'll do for their "environment". Doesn't mean we can't have our cake and eat it, too, but I clean my tanks every week with water changes ranging up to 50%. That frees me up to keep whatever kind of fish I'm prepared to properly care for with regard to water parameters, etc. You can make "smart" choices but I've yet to hear of a successful, maintenance-free aquarium...unless it's empty, of course. :) Oh, the fish you're referring to is a Plecostomus catfish, specifically Hypostomus plecostomus. Not the only variety of Pleco available, by any means, but this is probably the species you're asking about.>> Jasen Stoeker <<Tom>>

Question...UG Filters-Hydrogen Sulphide Factories  - 5/18/2006 I have a 46 gallon aquarium with a bow-front.  Is it possible to use an undergravel filter with this aquarium, since it is not rectangular? <Fred, is there any particular reason you want to use a UG filter? These guys are maintenance headaches.  You would be much better off with a bio-wheel type filter if expense is the concern. Do read here and then decide.   http://www.wetwebmedia.com/FWSubWebIndex/ug5proscons.htm James (Salty Dog)> Fred Stoeker UG's....not my choice  - 05/17/2006 Dear Crew, <Hello.> Can I use an undergravel filter in a 46 gallon bowfront aquarium, <...You can, I wouldn't...not a fan of UG's myself.> even though it is not perfectly rectangular because of the bowed out front? <UG's in my opinion are obsolete, if this is freshwater aquaria look into a nice  canister filter like an Eheim.> Fred Stoeker <Adam J.>

Mainly FW plant selection, growing with UG filtration  3/21/06 Dear Bob / Sabrina I have been keeping tropical fishes for the last couple of years. I have 5 Angels, 3 Clown Loaches & some tetras in my aquarium. During this period I tried so many times to keep real / live plants in my 5 feet long tank which is based on under gravel filters but I never got success :-( again I had to decorate my aquarium along with Plastic Plants. This time again I am trying to keep the real plants. I need some information from you 1. Can I keep them in Under Gravel filters based tank. ( Here in Pakistan I have seen many aquariums which are full of live plants and are running on Under Gravel filtration ) <Not all species... or not w/o "blind-potting" many of the rooted varieties (in their own substrate, containers, or with a solid barrier placed on top of the UG plate between the gravel...> 2. What species of plants should I keep ? I mean what types of plants ? I intend to keep Hygrophila, Cabomba, Vallisneria, Java Fern & Cryptocoryne, are these plants suitable for keeping with each other. <Posted: http://wetwebmedia.com/PlantedTksSubWebIndex/AquariumGardenSubWebIndex.html> 3. If the above mentioned plants are o.k. then what are the lighting requirements for these plants and what types of fishes I can keep along with these plants <Also posted...> 4. Here in Pakistan a local plants dealer told me that Java Fern do not grow well if it is potted in a gravel. Placing it on a Bog Wood will do better. Is he right ? <Yes... posted> I am a regular visitor of your website and I think it is very informative. Wish you good luck in your future endeavors Very Best Regards Shany Karachi, Pakistan. <Thanks much. Bob Fenner> Looking For Undergravel Filters  9/19/05 Hello! I am currently searching for an underground filter system for a 46G freshwater aquarium.  The dimensions are 36.5" X 16.5" X 21".  Can you please recommend the correct size for this 46G bow-front?  Also, is there a company that makes "custom-fitted" underground filter systems?  Thanks for your time. Regards, Shelly Hentges < Go to DrsFosterSmith.com. They have an undergravel filter by Perfecto that is 34.5" x16.25" (#MA-128358) for a 50 or 65 gallon tank. Pretty darn close. Nobody makes custom undergravel filters that I know of, but the one mentioned above will work just fine if you really want an undergravel filter.-Chuck> Cleaning Undergravel Filters - 08/25/2005 I have two underground filters connected to  power-head filters, and I was wondering, how you can clean underneath them? <Very, very difficult - and a great question, besides.  The best idea I have been offered is to run an airline hose down the lift tubes and start a siphon....  if you have an open-top-type stand, you can get underneath and see where the problem areas are to get 'em cleared out.  This is not a great solution, but it's better than doing nothing!  Another option would be to do a reverse-flow UGF (powerheads would drive water IN the lift tubes, and out through the substrate, rather than the opposite).  You'd want it cleaned out prior to making this change, though, or all the gunk underneath will get stirred up.  My preference is just to not use UGFs when avoidable.> Thanks for your help! <You bet!> Christine <Wishing you well,  -Sabrina>

What's that smell??? (10/22/03) <Hi! Ananda here this afternoon...> I have had a 3' aquarium for 7 years and had encountered few problems . I have recently added some new fish after a long time with only a few fish in the tank. I now have a major smell problem with the tank. I have cleaned it out more often and I am wondering if I have cleaned it out too much and removed too much dirt for the under gravel filter to work? Please help if you can my living room smells like the bottom of a pond!   <It's likely there's something stuck under the undergravel filter plate, rotting away, and producing hydrogen sulfide. You may need to tear the whole tank down to clean under there and find the culprit. To prevent another occurrence of something like this, I think the new fish deserve a new filter. There are a number of easier-to-maintain filters available now. For a 3' tank, without knowing how many or what kinds of fish you have, I would suggest looking into the Penguin 330 or one of the Emperor filters (click the Drs. Foster & Smith icon at the top of the Daily FAQs page and wander over to their filtration section).> Karen. <Hope this helps. --Ananda>

Re: What's that smell??? (10/22/03) Hi Karen here <Hi! Ananda back again, here...> Thank you for you help. I have actually solved the problem already , you were right though. Both up lift pipes were loose and blocked. the fish are happy and the tank smells sweet!. thanks again Karen. <Glad to hear you found out what the problem was. --Ananda>

The Smell Returns (11/01/03) Hi again, <Ananda here, back for another round> In trouble again , we now have a foggy tank and a white mold like growth in the up lift pipes and another smell hard to describe but just not nice. <Ugh. Time to partly disassemble the UGF and see what's under the plates, I think. I did that, once...and switched to a different type of filtration.> Can you help? <Got airfare? ;-) Seriously, though, I think you may have some blockages in the gravel... and I think the "white mold growth" is a symptom of a filter in need of cleaning.> I did wonder if it was just that the filter was not active yet? <Hmmm? Did you get a different filter with bio-filtration capacity? Or are you referring to the UGF?> Karen <Maybe try soaking your uplift tubes in vinegar, then water, to clean them? --Ananda>

No More Smell in That Tank (11/04/03)  Hi again  <Hi! Ananda back again.>  Thank you for your help again.  <No problemo.>  All is sorted. I had emptied the tank and cleaned under the UGF and then the tank went cloudy and smelly.  <Ah, that explains it. By emptying the tank, the gravel got disturbed and some of the nitrifying bacteria got killed off. Thus the cloudiness.>  After I had E-mailed you I cleaned the up lift pipes and did a partial water change every day, after about ten days all is well the fish are happy and the tank smells sweet again. Thank you again for your help.  <Sure>  I have just set up an additional tank and I am increasing my collection of fish. We have a small nursery tank as well with balloon mollies, Dalmatian mollies and white cloud mountain minnow fry so we have lots of fish to look after.  <Do you know what you're going to do with all those fish? You can only fit so many tanks in a house, as I've discovered....>  I am also going to set up another 3' tank as soon as I can as a friend has sold one to me very cheap.  <That's a start.>  Thanks again for your help. Karen  <Best of luck to you and your fish. -- Ananda> 

Gravel Filtration Do you recommend gravel filtration? <Method of filtration depends on many factors, freshwater, saltwater, fish, reef, etc. Please surf over to http://www.wetwebmedia.com/ and choose your weapon from the headings...marine or freshwater, and then the sub headings for filtration. It is vital to factor-in the type, habit, feeding, waste production and adult size of the inhabitants you are interested in, and what is required to provide them with whatever it takes to thrive in captivity. The web site will provide you with all the information needed. Enjoy! Craig>

Reverse-flow or normal flow? Date: Thu, 10 Mar 2005 Hi, <Bonjour!> To put you in the situation, I have a 75 gallons with 19 adults herbivore Mbunas, 1 AquaClear 500, 1 canister Fluval 304 with sponges, Rena BioStar and crush corals inside. Also UGF powered with 379 gph powerhead on normal flow in a corner. At the opposite corner, an air inlet pull water in normal flow too. The gavel thickness is about 2-4 in. depending where. The food I use sink very quickly and it goes in the gavel following the water flow. <I see> The thing is that I have a certain numbers of dead spot due to rock caves and hiding places for Mbunas. I thought it will be better to push the water under the gravel because at weekly water change I don't want to move all rocks away. If you think the idea of switching flow is great, I will put two more powerhead and remove air from the UGF. <This is what I would do, oui> Thanks a lot, Philippe. My English is not very good so it could be difficult to read.... <No problem. You are making yourself understood. Merci, Bob Fenner> 

UGF etc, filters, cycling, FW I have several questions. <Hope we have as many answers> I am going to put a UGF in a 50 gallon tank. Am I correct that you need a 2 inch gravel bed? Now do you layer this gravel evenly over the plates or is it better to have it sloped higher from back to front? <Mmm, about right... depends on the grade, make-up of the actual gravel... and flatter is better, more functional> Also do you recommend power heads over air pumps and if so how do you know the flow rate? <Actually, airlift works quite well... powerheads are fine though... a rule of thumb... no more than two gallons per minute of actual flow per square foot of plate/bottom> For instance a 50 gallon UGF plate comes in two separate pieces so a 48 x 13 is really 2  24 x 13 plates so is the flow rate for a powerhead determined by total tank volume or by gravel bed size? <Ahh! Both... and finer gravel can "take" higher flow rates...> The reason ask this question is because I also have a 72 gal bow front that would take the same filter plates but has 22 gal more water. Is it possible to have too much aeration under the UGF plates? <Yes> Next I understand the cycle process and the need for water changes during this time but how much water and do you vacuum the gravel during this cycle time? <As little as possible... disrupts the establishment... I would only change the water (not disturb the gravel) and ONLY if ammonia or nitrite exceed 1.0 ppm> Also I have some established biological gravel how much do you add to the new tank <A few pounds... even "dirty water" vacuumed from it would do> also I am going to put an Xp1 canister on the 50 gal and I already have a cycled XP2 with 20 BioStars how many can I take from that I will put new ones in place of what I take out) without creating problems? <About half> Thank You for your help Heidi <Thank you for your thoughtful questions. Bob Fenner>

Re: UGF etc Thanks for the help! I have searched and don't seem to  find  definitive answers. So here comes more questions. So if powerheads are used the 50 gallon UGF would use the same rated powerheads as the 72 gallon bow front UGF because the gravel beds are the same dimensions? <Yes... FOR the purpose of the filters themselves... think about this.> Or since the 72 gal is 4 inches deeper do you need more power to drive the UGF? <No my friend... the pushing/pulling through the filter plates, gravel will/would be the same irregardless of the depth of the system> If so how do you know how much more power is needed? So if using an air pump to drive UGF do you recommend airstones? <In general, yes... Good flow rate, easy to check on... adds aeration, breaks up surface film... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwugfiltr.htm and the linked files at top> In the instance of the UGF for the 50 g being 2 separate plates, how many lift tubes per plate would be used and how would you be able to tell if the flow rate is where it needs to be and not too much or too little? <I'd only use one lift tube per plate> Is there an acceptable way to calculate and regulate the flow when using air pumps? <Not generally necessary... can be estimated, even physically measured if you'd like to discuss this> Does having the elbow on the lift tubes totally submerged or partially submerged change the flow rate? <Yes, decreases somewhat... worth the trade off in circulation> I understand how to calculate flow rate per min with powerheads but not with air pumps. In the instance that powerheads are used  would just 1 powerhead be used per plate and does it matter which lift tube is used? <The ones in the corners, better>   There is so much that I still don't know. Hope I am not driving you nuts with these questions. Thanks so much! Heidi <Too late... already there. Bob Fenner>

Removing a UGF Hi Don, Dayna here again, thanks for the fast response! Could you give me a few pointers on how I would go about taking the UGF out? Thanks again. Dayna <First I would add another power filter and let it run a good month to become established. Then get out as much gravel as possible and give it a good rinse. Lower the water level to about half. Have replacement water ready. Lift the plate slowly at one side and with a siphon draw out as much of the junk as possible before it floats away into the water. A lot still will, but it will either settle or be filtered out. Replace the gravel and water. Give it an hour or two then replace the filter pads. Leave the bio wheels alone. In a day or two use the gravel vac to get any junk that settled. Test for ammonia and nitrite spikes and do water changes to correct any spikes until things settle down>      

UGF and Catfish Questions I hate to inundate you with questions, but I can't seem to find the answers to this anywhere else, and you guys always seem to have the right solutions. <No problem, Don here> I have been running an undergravel filter on one of my tanks but I now want to change and use canister filters instead. What do I need to do to make the transition? Can I leave the plate in and just take out the tubes? Should I wait a few weeks to allow the canister filters to get established? (I plan to use an Eheim 2229 wet/dry and an Eheim 2260 on a 215 gallon tank) <You want to remove the plates. Big job in a 215. If you can move the fish for a few hours, do it. If not I would start by siphoning out as much gravel as possible. You can rinse and reuse. Try to get the siphon under the plate before you lift it too far. There is going to be tons of nasty stuff under it. You want to get as much out before it floats away into the water. Don't do this until the new filters are cycled. Watch for ammonia and nitrite spikes afterward>     Second question: is there any catfish similar to the giraffe cat that cleans the gravel like it does but does not get as big as the giraffe? <There is a dwarf giraffe catfish, to 8". See here: http://www.planetcatfish.com/cotm/2003_08.php Third: is it necessary to have a CO2 system for a planted aquarium? <No, not for most plants, but some need it and all will benefit. If you add one watch your pH> Last question: can Plecos be used in a fresh water planted aquarium? <Yes, most well fed Plecos will not eat your plants. There is always a chance however, if we're talking about the Common Pleco. I have three Big Spots and three Bristlenose in a lightly planted tank. Never lost a leaf. There are also many meat eating Plecos>   Thanks for all of your help, Jim G Gravel, UG Filters Hi There, Another question from an eager listener....  ;) With my current set-up:  125 gallon tank, 2 baby Arowanas (jardinii and yellow tail), and 2 Emperor 400 power filters......I am wondering if I can put gravel to cover the bottom of my fish tank???   I usually just scoop up every morning and night the "poops" of the fishes and 20% water change every week to avoid ammonia and toxic build up. <<Hi there. First, you should buy extensions for your Emperor intakes, that will help a bit with circulation, the filters will be able to suck up waste from a lower level.>> What are the disadvantages of putting gravel in my tank?  How will I be able to clean it and remove the "poops"? <<You can buy a gravel siphon at any decent Local Fish Store. (LFS).>> Will just stirring the gravel and using a vacuum do the trick to clean them? <<Gravel vacuuming will do the trick. Vacuuming with your siphon should be done weekly, when you do a water change. Not only does a siphon remove detritus from the gravel, it removes water at the same time. Use a good thermometer, take it to the sink with you when you start filling buckets to re-fill the tank with...the water should be the same temp! Add dechlorinator to each bucket as you re-fill. Better yet, buy yourself a Python. Ask for these handy hose kits at your LFS.>> Will I be needing an undergravel filter for this set-up?  Or will my 2 Emperor 400 power filters be enough?  What if I make it 3 Emperor 400's? <<Undergravel filters are more trouble than they are worth, IME. Your two Emperors should be sufficient for the time being, you only have two small arows in this tank. You should keep in mind that with a larger bio-load, you may need to add filtration later. In other words, if you add more fish, or when your arrows are about 6-8 inches or so you may need to upgrade. You should keep an eye on their growth and on the tank, an overly dirty aquarium means insufficient filtration, not enough water changes, and/or inadequate maintenance is being done. You will realize it IF the time comes.>> It is just a laborious duty to have an undergravel filter.....plus in time, a build up of wastes...will lower the ph of the tank......are some of the reasons why I am hesitant using undergravel filter. <<I agree. There are many filters out there that are much easier to maintain, and do a great job. No need for UGF's at all.>> Thanks, Antonio <<Welcome. -Gwen>> 

Undergravel filtration, and funky water quality Dear fish saviors, <Good afternoon, Kaz - Sabrina here with you this lovely (rainy) lunch hour> I've had a long and generally successful fishkeeping career but this year 2 of my goldfish died (at ages 19 and 17 years old). <Oh my.  What a loss.  I'm so sorry to hear that.> Only one sad survivor was left. I was away, the water went 'off' and they died :( Anyway, I worked hard to stabilize the tank with the Lone Black Moor (who had some scars, general poor condition, floating prob.s etc). He came good and after a few months I got LBM some friends - a small comet and a small fantail. My problems came back. The new guys were hungry all the time and I am guilty of giving in to their shameless begging. <Just say 'no'! to fish obesity ;) > Also I changed fish food on advice of LFS (sinking pellets, 34% protein) and am not sure if this has contributed to the instability. <And what were you feeding with before?  Do your guys get any vegetable matter?> LBM seemed happier and with more energy but developed two little white spotty bits on his head. These then seem to have gone away (I treated with fungal cure) but he has a new one further back on his head. <Can you describe this in a bit further detail? Do the spots stick out? Or are they pits?  Are they fuzzy looking?  Waxy looking?  Look like cauliflower?  How big are they?> After uncontrollable Ph problems I checked with LFS and changed my filtration system (from charcoal and wool type filter to undergravel filtration).   <Filtration isn't very directly related to pH swings (except as far as organic materials building up), I can't imagine why they told you to switch....> But my question is (I know its very naive but..) how to I keep it clean? I have used the gravel siphon cleaner thingie and have done a 25% water change since I got the UGF two weeks ago but my plants are disintegrating. <Argh.  UGF and live plants do *not* play well together, and there's not much of a way to make 'em work out.  Your only plant species is elodea, correct?  Perhaps try letting it float only, and see if it grows any better.> We work in centimetres and litres here in Australia <I wish we did, too!> so I'm not sure of how many gallons but tank is 24inches x 12inches x 12inches. It is certainly not overcrowded, with the LBM and his two new little friends and the plants are (or were) Elodea. <Okay, I do believe that's about 15 US gallons.  I usually recommend goldfish to be kept in tanks where they'll have 15-20 gallons per fish; they are hefty waste producers, and can foul the water very, very quickly.  Three goldfish in a 15g aquarium with an undergravel filter.... well, I can guess that in short order, you'll have some serious nitrate problems, possibly other water quality issues, even with the best maintenance possible.> How do I clean the crud which I assume is collecting under the plastic UGF tray??? <Wonderful question.  I've heard using silicone air hose fed down the lift tube(s) and siphoning from there will help get some of the grunge out.> Should I go easy on the gravel siphon thingie? <Gosh, no.  Vacuum like a madman.  And slap that wet/dry filter back on the tank, too.  Then when you vacuum your gravel, let the filter cartridge stay in the filter so you've got plenty of bacterial life still around.  Probably only vacuum about half the tank each time, as well.> Did another partial change today and the fish are happy and starving but there are lots of floaty bits of plant matter still in there. Should I siphon these out? <Yes, absolutely.  Dead, decaying plant matter will contribute to ammonia problems just as will fish waste.> When I do water changes I use Cycle, ammonia treatment, <Skip the ammonia remover, unless you're registering ammonia on your ammonia test - oho, I should mention/ask that you should be testing for ammonia, nitrite, nitrate, and pH - if you don't, please do get yourself a kit, so you can have a better grip on your water quality.  And far better than using ammonia remover schtuff is to simply do more frequent water changes.> pH stabilizer, <What's the pH out of your tap?  It's far more important to keep pH stable than to keep affecting it chemically; goldfish are very pH tolerant, so if your tapwater's anywhere close to decent, they'll be fine with out pH altering chemicals.> StressZyme, Tristart chlorine and chloramine remover. I let the water sit for 24hours, make sure the temp is the same etc. <Wonderful.> My main concern is that I found out from your site that UGF require lots of work but what work? can you let me know what I need to do to keep my friends happy! <Mostly the weekly vacuuming of gravel, jamming air hose down lift tubes.  UGFs must be cleaned thoroughly and religiously, lest all that waste building up in the gravel begin to poison the fish.  If it is in any way whatsoever possible, please please try to get a larger tank for these fellahs.  Believe me, they'd thank you for it.  Wishing you and your scaly pals well,  -Sabrina> Cheers, Kaz

Undergravel filtration, and funky water quality - take two Thanks, Sabrina, Will head off and get the testing kit today. <Wonderful!  Try to get a liquid reagent type kit, the test 'strips' that you just dip in the water can be grossly inaccurate.> I suppose what puzzles me is how come I could keep the same number of goldfish (and same type) in the same tank for 8 years (since the last fish arrived) with little problem - long living and happy fish - and now everything's going wrong??   <Likely when you went away and the water turned south started your problems.  These are really, really messy, waste producing fish, and in such a small tank, missing even one regular water change will result in a buildup of waste toxic enough to kill them.  Hence the major reason I usually recommend 15-20 US gallons per goldfish, there's SO much more room for error in a larger tank.> The white spots on the remaining old fish are small and very white, about large pinhead size, they seem to stick out and after a few days just fade to nothing. <This sounds like either Lymphocystis or fish pox, both of which can be found in goldfish from time to time.  Lymphocystis is kinda cauliflower-like in appearance, whereas fish pox looks rather waxy.  Both are viral infections, and there is no treatment.  Fortunately, neither are often fatal.  Just maintain the best water quality you can, with regular water changes and testing, and he should be fine.> Apart from plants in the tank I don't give them any veggies - should I?  Thanks!  Kaz <Couldn't hurt.  Mine adore unsalted canned peas (rinse, and squeeze the inside of the pea out of the shell).  Blanched zucchini is another good one.  Lots of goodies out there for them, but just the Elodea will do, if necessary.  Best wishes to you,  -Sabrina>

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