Can you tell me about undergravel filters? (Lots of questions)?

Question

I am about to set up a 10 gallon aqaruim, right now I have my poor goldfish in two one gallon tanks each with air pumps and undergravel filters... aside from the small size of the tanks for the goldfish is that a typical small tank set up? Will it be effective and healthy (with different fish of course... maybe betas?)?

I didn't realize goldfish need so much space untill shortly after I got them... they each need ten gallons but I'm think moving them to the 10 gallon tank I was able to get will be a little better for them for now at least.

Can I take out the two small undergravel filters and use them with the airpumps? Or use one of them in one area of the larger tank?

Also, can undergravel filters be harmful to fish??

And I need to get a filtration system as well... is that something that is neccesary to have when you use an undergravel filter in a larger tank? (I plan to get one whether or not I use the undergravel, I'm just curious).

Thank you for the help! :)

I was going to use a bubble curtain in the ten gallon tank and another air bubler ( i have 2 airpumps), will that help the fish a little considering a lot of people say goldfish need 10 gallons each?

Answer 1

Where to start?
10 gallons is fine for 2 goldfish, you do not need 10 gallons apiece but the larger the tank, the better. 20 to 40 gallons do not need to be cleaned as often and do not require as many water changes. with 20 gallon maybe 5 gallons every other week.

with a 10 gallon, you will need to change up to 3 gallons at least once a week. especially if you put other fish in because of the amount of waste produced in such a small space.

Personnally i do not like or use undergravel filters because i have a planted aquarium and do not want to have to break it down to clean the filters every few months. I vacuum the gravel every two weeks when doing water changes to remove the waste that lays on the bottom.
But yes you can use the old filters but they will not be as effective because they will not fill the tank bottom as well as if you had a single filter. you can run both filters on the same air pump.

If you are getting a new filtration system anyway you won't even need the undergravel. the kind that hang on the back of the tank work ok. the kind that pump water out of the tank and spray water on a wheel are probably the best. they are called wet/dry.
then there is the canister type(water pump filters). which should cycle the tank 3 or 4 times per hour and are great for quick cleaning of floating particles.

I have and prefer a "Wet/Dry" type filtration system and a small canister for water polishing which can also be used to drive a Biowheel. (see marineland link)

One other thing: Goldfish do fine in a Planted Aquarium even with out filtration because the bacteria in the soil/gravel break down the waste and turn it into fertilizer for the plants which produce oxygen for the fish. Just something to think about when you can't think of anything to do with the 1 gallon tanks.

Answer 2

I personally don't like UGF, especially for goldfish. Unless they are run with power heads they won't do what they are made to do correctly and can just cause gases to form under them and if it escapes can kill your fish. Goldfish do better with power filters anyway and you can get a good one for a 10 gallon tank for around $15. Use the air pump that you have for the UGF and buy an air stone for the fishies to play in, it also makes the tank look nicer.

10 gallons is OK for now until they start to grow so start saving for a bigger tank. To save you some money later on get a filter for this tank that will be strong enough for the bigger tank too. That way you won't need to buy another one and it will already be cycled. Just make sure the filter will do at least 10x the amount of water, so for the 10 gallon it would have to pump 100 gph and if you get a 20 gallon later on then it should do 200 gph. Most come with a control valve to slow the flow of the water if it is too strong on the 10 gallon.

Once people give their goldfish enough room and they actually live longer then a few weeks and can grow they always want more so think about that too when you are deciding on a bigger tank. If you would like to learn more and maybe see some pics of some nice healthy goldfish check out this site and join the forum, http://kokosgoldfish.com/
They can tell you even more about what filters to use and answer any other questions you may have.

Answer 3

The small tanks will be fine for betta's or guppies the way they are set up.


I don't really like undergravel filters. Because they just pull all the waste down to the bottom - so it appears clean - but all the toxins are just pulled down to the bottom. They do not really clean at all.

All your 10 gallon tanks needs is a nice large side filter. (The filters that hang on the back of the tank)

As you know, goldfish are very dirty fish. So I recommend buying a 40 gallon top fin filter (Cheap, around $25). It'll keep it rather clean longer, and it will provide oxygen in the water (no need for the bubble wands).

Top fin filters are cheap, but they work great.

Change the filter pads once a month to twice a month depending how dirty your guys are. And do a 25% water change once a month or twice a month.

Also only feed them one-two times a day. They may act like they are starving, but thats really all they need. Feeding them more will cause them to grow faster and the water to get dirty faster.

Also I recommend pellet food over flake food. The usually eat all the pellets but the flakes that sink to the bottom stay there and makes the tank dirty.

Good luck.

Answer 4

I had aquariums for years, long before they had the easy to use ones of today..I've been through the ones with fiberglass floss and charcoal filters. The new ones are easy - undergravel filter works great but remember to put enough gravel on top of it for proper filtration..if you get the kind that has charcoal cartridges at the top of the tubes that filter back into the tank then don't forget that you have to change them about every 2 weeks or so depending on the types of fish and quantity of fish in your tank. I used to do a 20% tank water change out every 2 weeks as well. for the fish- goldfish are scaled down domesticated carp, they like a little bit cooler water than so called tropical fish. gold fish also produce a lot more amonia than other fish. - just some things to consider before mixing fish types in your tank. Plus there are several species of fish that need different numbers of them in the tank, some fish do ok when there is one of their kind, others benefit from having a small school of their kind..sounds strange but it does affect their over all social behavior. best advice I can give you is to get a good book on aquaria and read it before you decide - those gold fish will grow larger the larger the tank you put them in too. Have fun and best of luck. - they don't need ten gallons each but if you want them to get large I would only put 2 - 4 in a ten gallon tank - the bubble curtain is a good idea..mine liked to play in it *L*

Answer 5

Undergravel filters are just about the best biological filters you can get, because it uses the gravel you have in the tank already to do the job.

The reason I don't like them has been stated already - the waste gets trapped under the gravel and keeps building and building, giving the filter more and more of a chore to do as time passes. Eventually you end up with a sludge of crud under the filter plates that can only be cleaned by completely dismantling the tank - both a pain and stressful to the fish.

Power filters these days are economical, very effective, and easy to clean, and I recommend them over UGF any day.

Goldfish in general do need as much space as you can give them - many people don't realize they can live over 20 years and grow to a foot long in the right conditions.

Answer 6

Essentially, you can use any powerhead with any undergravel filter. You may need to do a little rigging to get the powehead to fit into the uplift tube, but that isn't usually too hard. You didn't say how big your tank is, so I can't advise you as to the size of powerhead you need, but don't get one that's too large (in terms of gallons per hour or per minute that it pumps). In a smallish tank, many powerheads produce a strong enough current to smash your fish all around the tank.

Answer 7

Under gravel filters create a biological filter over a period of time, the same way nature does. It will develop a bacteria that destroys fish waste and uneaten food. As far as using it in your ten gallon, I wouldn't do that unless your strapped for cash. Get a size to match your ten gl. tank. Outside filters will clean faster and provide more cureent in the water. the bubble wand will help oxygenate the water also. Don't over crowd the tank unless you provide plentey of oxygen transfer, which happens at the surface, the water gets very little oxygen from bubbles.

Answer 8

I personally prefers an external canopy filter where you can clean the filter once a while by washing it thorouhly. It comes in two pipes draining water from the tank to this filter and pumping filtered water back to the tank. With undergravel filter, fish waste will still be stucked within the layer of sands and can continue to degrade the water especially with gold fishes having large amount of waste disposal.

Answer 9

Undergravel filters are the most common type of biological filter and work by pulling water down through a bed of gravel at the bottom of the aquarium and pulling it up through the uplift tubes. Reverse flow undergravel filters are set up to pull water from the top of the aquarium by pushing it down the uplift tubes and up through the gravel. Reverse flow filters are slightly more efficient since they take water from the top of the aquarium which contains more oxygen.

Since nitrification is more efficient in the presence of oxygen and the air contains about 20% oxygen, as compared to about 7% oxygen for water, trickle filters were developed in the 1980's which increased the efficiency of biological filters dramatically. They place the bacterial growing medium, filter balls with large surface areas, in the air (usually outside the aquarium) and trickle the water to be filtered over them. Many kinds, sizes, and shapes of trickle filters have been in use since they were introduced. Although many trickle filters are external devices used in a sump or hang on the back type of filters, several manufacturers including the "Sea Clear System II" aquarium contain trickle filters built into the back of the aquarium itself. The problem with trickle filters is they usually produce high levels of nitrate, and so are not often used in reef aquariums or other situations where nitrates are undesireable

Answer 10

Don't be discouraged to use UGF's. Yes, they build up biomass that has to be cleaned, but that is easily accomplished with a simple siphon hose and vacuum tube. Use it 2-3 times a year, and you're fine. Also, you can replace those air pumps with an immersible water pump to improve flow. UGF's are simple, reliable systems. I've never had a problem with one. UGF's work best when they are under the entire gravel bed. Don't split it up to use in two separate tanks.