I'm not sure Andy ...

Myself I have an undergravel and a mechanical filter on the back of the tank ( 20 gallon ) .... I use eggcrate ... plastic screen .. and PVC pipe to make my own system ( about $15 ) and run with an air pump but I suppose one can use power heads ...

My thought is the undergravel provides a large area for benificial bacteria compared to the mechanical filter which agitates the water surface in a different way and is easier to clean ... so I like both .. but my tanks have always been 30 gallons or less ... there are other options with a 90 gallon.

I'm a filter nut .. I would like to add a small canister filter to my 20 gallon... I hope to get a 250 gallon soon ..

A siphon cleaning kit sold in any fish store can be used to clean the gravel ..

Good Day ...

Undergravel filtration is still an excellent form of filtration if the fish in the tank do not dig up the gravel like cichlids or some goldfish. If the fish dig they ruin the effectness of the filter. Used with a cannister or hang on the back type of filter you will get wonderful filtration, chemical, mechanical , and biological. In a tank as large as a 90 gallon I would recommend using power heads instead of an air pump to power the UG system, it moves more water and will do a better job for you.

I have two large goldfish (black moors) and do not use an undergravel filter. The tank is somewhat "bare bottom" with several 2-3 inch rocks, pieces of driftwood with java fern, and some regular white gravel that "moves" as the fish play with it.

I use an Eheim canister filter that is rated appropriately for my tank and it provides all the biological and mechanical filtration. The tank has been going almost two years with no disease issues.

If you choose to use an undergravel filter be sure to keep the gravel well-siphoned!

I had undergravel filters for small tanks up until 1997 when I switched over to the BioWheel system.

I like the BioWheel so much better there is no comparison. With the BioWheel, I can grow lovely plants. Undergravel filters tend to retard plant growth unless they're planted in pots. I also found that my gravel would get unbelievably filthy with the undergravel filter - I guess because it tends to pull detritus down. I haven't had that problem at all with the BioWheel.

All in all, my water conditions have remained much, much more stable, water is clearer, conditions on the whole are much cleaner with the BioWheel than with the undergravels I used to have. And this was with small tanks - 10 - 30 gallons. I can't even begin to imagine what it would be like maintaining an undergravel filter in a tank size of 90.

Some people still use outdated UGFs for their own reasons and love them, but i'm not one of those people. I'll be blunt. I ~hate~ undergravel filters. IME, modern filters are much better and never produce the "breakdown nightmare" when all the gunk under the plate reaches critical mass and kills off your entire stock, often with very few indicators to warn you that's about to happen (unless you are a very diligent water tester, and most fishkeepers aren't).

When the time comes to clean out that gunk under the plate, you have to completely break down the tank, remove everything in it and basically set the whole thing up again. This is very stressful on both the inhabitants and the keeper, and in a typically stocked tank, ought to be done annually. No thank you!

There are probably a few situations where an UGF makes sense, and some of these issues can be lessened by running it as a reverse flow undergravel filter (i.e. you set it up so the water travels under the plate and up through the gravel, minimizing the gunk build up under the plate). However in most cases you are better off with a quality external canister like an Eheim, a power filter that has an open space for media which can be customized, like an Aquaclear (as opposed to one that only accepts narrow cartridge refills), or some combo of both. Bio-wheel type power filters are fine if you like them, i don't like the splashing personally and prefer to use other methods of gaining surface area for the beneficial bacteria.

I've been using UG at home either alone or in conjuction with cannisters or bio wheel filters and never had a problem with too much gunk under the plates. Many of the customers at the store I work at do too along with most of the over 200 tanks in the store, some for over 20 years with happy healthy fish. If you keep the gravel clean by siphoning and once a year use your siphon to pull the gunk up from under the plates (I push the gravel back, pull the lift tube out then use the siphon to pull any glunk hiding under the plates out without tearing down the whole tank While they are not the latest hottest thing on the market UG filters still work and can be useful in the right situation.

If I setup a new UGF I would reverse the waterflow down the tubes and blow the water back up through the rock. there was one setup in an aquarium magazine and the floor of the tank and the grave stayed clean. There are new power heads that are reversable flow and will do this already. If you are keeping goldfish use large river stones instead of gravel. They can still pick the rocks but don't move them or choke on the gravel.

On my 150 gal freshwater I use a undergravel filter and a Hagen Aquaclear 500 and a Eheim 2217 canister filter. Any system that relies on one filter is too risky for me.

I may go that route, James.
I have this mother-of-all piston pumps that will run the undergravel filter, and use an AquaClear 500 to do the rest. Should suffice in a 90 gallon community tank me thinks.

-andy

I don't have any UGF, but my brothers swear by them!

Undergravel filters are wonderful devices for an ambitious hobbyist - terrible for the lazy hobbyist. Regular, deep vacuums keep the substrate clean. I've been running one in a 29 gallon tank for several years and I've never had to "break down" the tank. I use a small, canister type filter also, that I installed mainly for additional aeration and chemical filtration. The riser tubes have small compartments that hold a minimal amount of charcoal. The undergravel filter seems to pull everything down into the gravel bed to the extent that the canister filter rarely accumulates much debris. I have no complaints whatsoever. Some people don't like the sound of bubbling water (if you use the airstone method). My wife and I actually like the sound that this produces.

A word of caution when siphon cleaning the UG filter. My 17 year old 150 gal Perfecto tank started leaking after I did a major siphon cleaning. I think I pushed down too hard on the siphon tube and disturbed the silicon sealant. $400 mistake and my new Perfectos' glass is about 1/2 the thickness.

Yikes! Maybe it's not worth it. When I went into Aquarium Adventures last Sat. night, I asked about UGF's and they said that they don't really carry them anymore. He said he had one for a Hex tank. Hmmm..
BTW, James. What are the dimensions of a 150? I'm shopping around (in my head at least) for a new tank. I was thinking I'd want something more then a 75, and the 90 looked too tall and squat.

thanks,

-andy

Hey Andy... I'm pretty certain they have a long and wide 90 out there!! ??

As far as UGFs... they sell those grids that you use under the gravel... I thought these were standard sizes? Just a matter of fitting them into the tank (and cutting down if necessary?) And then just setting up the other equipment to push the water up and under the gravel (using airstones??)

I don't have UGFs, but this was my understanding of the basics??

I have a ugf in a 7 gallon hex I was given. I have issues with the power head sucking rocks.

Is the plate just ill fit? I really don't want to tear it down since it's a fry tank and the tank itself is hard to get into.

Adrea

This is kind of the same topic as to gravel or not to gravel a pond. There are people who have had success with both and others that have not been successful with an UGF. I like the idea if you need the bio-filter aspect but they are sometimes hard to get working correctly. To check you need to see what's under it and in most cases that's difficult. Most stands do not have a view under the bottom to see and it's hard to move everything without cleaning it out. My tank has large 1" and bigger river stones with spaces between. My ryunkins root around between them and even push them around to get what's down there. i only use it because I don't like the bare tank look. I use a gravel vac for water changes and it picks right up around the stones so it's easy. Most fish stores are not recommending them anymore and I think it's because people are lazy and they become nasty and stagnant underneath.

Pfrog, I think the 150 gal tank is 6'L x 18"D x 27"H. Cost was about $400. There are a few diff sized plates, the 150 uses 2 plates. Perfecto makes the UGF's for all their tanks. Isis, a powerhead in a 7 gal sounds like it would be too much current for fry, wouldn't an air pump be better?

James, ever notice that although some folks feel the UGF is "out of style", most of the Salt tanks at South Shore still use them?

hmm...

-andy

If you compare it to a large sump filter with skimmer it is less efficient. But compare it to a hang-on or cannister filter and it has a much larger surface area thus more capacity to breakdown ammonia. Also doesn't crash like a regular filter when a complete filter change is made. The thing I don't like about sumps is they can be noisy, hard to set up, and the overflow setup takes up room in the tank.

I always had great luck with a good UGF with Hagen powerheads in conjunction with an Aquaclear back-filter. I never kept live plants though ... I know they don't really do well with UGF. In a strictly fish tank, the UGF acted as a great water polisher .. always had crystal clear tanks. I used a siphon vacuum every 4th water change or so, and never had any problem. If I were to get back into tanks, I would definitely go with the same setup. I saw the biowheel filter mentioned in an earlier reply, and I always read fantastic reviews on them as well. If you are considering an UGF, I would recommend one of the white ones with the holes smaller by the uptake tubes, and larger as the distance from the tubes increases, not the cheap brown ones that are uniformly perforated all the way across. Lastly, if Aquaclear powerheads are still made the way they were 15 years ago, mine ran 24/7 for 10 years and had only minor scoring on the impeller shafts.

I havent had good experiance with under gravel filters, but it could have been the fish. I decline againts it but i have never tried it with a larger tank

I've used UGFs in the past, and I always thought they were efficient and effective. I did vaccuum the gravel heavily - enough to suck the mulm out from below the plates to some degree.

I then moved to sponge filters, and now I don't use any filtration at all - just lots of plants!

I have a 55 gallon aquarium and had an undergravel filter and power filter which included mechanical, chemical and biological filtration. I just removed my undergravel filter and here are a few reasons why
1. They suck
2. I got tired of all the sludge that got packed into them. Now that I don't have one, vacuuming the gravel bed is sooooo much easier, i can basically just hover the hose above and get all the junk.
3. I got live plants and wanted a finer substrate. The live plants didn't grow to well with the undergravel filter, but i got some nutrient substrate and finer substrate, and mixed it in after i removed the UGF and everything has been great since.
4. My water was a mess with the UGF. It was stabilizing ok till i got the plants, but then everything went out of wack. But since i removed it, everything is now balanced.
If you don't want live plants, I guess the UGF is ok, i just think its a waist because all the junk gets packed INTO the gravel and you have to suck it out. whereas, with just a power filter, you turn it off, rinse your sponge or whaterver in some tank water, plug it back in and your good to go. Mine has a sponge, and carbon, and some organic stuff that floats on the top for bacteria to grow on. Also, as i said before, the gravel bed is so much easier to clean, i do about a 10% water change weekly and i don't have to worry about uprooting my plants to agitate the gravel, because all the junk stays on top.

I have a dome-fronted 5 gal sitting on my kitchen counter with some wild grey guppies from the lake and I have a UGF and some plants and a hitch hiking snail...everything seems to be ok: the plants are thriving, the fish are active and plump, the water is crystal clear...there seems to be some filter-type bias, wouldn't you say? Everyone has their favorite methods, how are we to know for sure what are the best methods of filtration, just trial and error?

The confusing part is that all filters will work for a while. People that have a tank running for 2 months think they have the answer, give it a year and you'll have some proof. Also if your only running one filter, what happens when it breaks/fails [this usually happens on Holidays or when your away]? The other thing is even the best filter still needs proper maintance. Water changes are just as important as filter choise. The amazing thing is how well the fish can adapt if the changes are gradual.

Makes sense to me. My "long term" experience is limited to a 10 gallon goldfish tank with an Aqua-Tech Power Filter and a gravel siphon every couple of weeks. I don't have the kinds of elaborate setups you all do...but am beginning to get the urge.

well, i have had aquariums for about 10 years now, so i think i have had quite a bit of experience with the different kind of filters. I have always had an UG filter untill recently. I did the monthly water changes. Now, i do weekly partial water changes of only about 10%. It's true, whatever filter you choose, there is always going to be maintenance, i jsut find the UG filters to be a huge pain.

Is it possible to use an UG filter for part of the tank (half?) in conjunction with a power filter on the back of the tank? I would like to successfully grow some plants and still have the benefits of a larger filtration area. Does this make any sense? Has anyone tried this? I want to set up a small (20 gal. high) community tank.

Sure.... been done before.

Have you done this? What size tank did you set up? Did you plant only over the tank bottom without the undergravel grid? How well did the plants establish?

ptconti, I have swords in my 150gal tank with a ug filter and they do ok. The gravel layer is thick [@4" and I use an airpump [i feel most powerheads push too much water]. Give it a try, if it fails put the plants in pots buried in the gravel. Use care not to disturb the roots when vacummint the ug filter.