Under gravel filter systems?

Question

Are they more efficient than just a filter that hangs on the side of the tank?
How often would they need to be cleaned?
Any other pro's or con's to take into consideration?

Answer 1

I would say the hang-on filter would be the most efficient, but it would really depend on how and why you are using it, what type of fish you are keeping, and how large your tank is.

The efficiency of either can vary greatly. For the hang-on, the main considerations are the type and number of filter pads and if the filter uses a biowheel. Multiple pads gives you more flexibility in cleaning, replacing, and adding other media, such as an ammonia or phosphate pad. You can also change one pad, and leave the other in so beneficial bacteria in the filter aren't all lost (important if you're cycling a new tank) at the same time. Biowheels add a greater level biological of filtration from the large surface area of the wheel where beneficial bacteria can grow. One drawback to some - the wheel can stop revolving, and unless the bacteria stay wet, the will die. A hang-on should filter between 5 and 10 times your tanks volume every hour (measured as gallons per hour, or GPH). If you have "messy" fish, or are close to being overstocked, you can move up one rating size.

An undergravel filter can be powered by and air pump (less efficient) or powerhead (more efficient). The larger the powerhead, the more water is pulled through the gravel and filter. With this method, your entire gravel bed becomes your biological filter, with even more surface area (surface of each piece of gravel) than the entire biowheel. Again, the powerheads are rated in GPH like the hang-ons and should be chosen for the same rate of filtration.

An undergravel only needs to be cleaned a few times a year. If you're running a powerhead with a reversable flow, just change the direction and all the stuff under the filter will be blown upward through the gravel (you do this after removing the fish from the tank, of course). If your powerhead doesn't reverse, you could try directing the flow from the powerhead down the uptake tube. The least preferred (by me, anyway!) is taking the entire contents out of the tank to clean.

A hang-on is much easier - pull one filter out, put another in. If you want to clean the entire filter, unplug, dump the water down the sink ,and take a brush to the inside of the filter well and the tubes (get a brush with a flexible handle for this purpose), pull up the impeller and clean out the well and impeller blades, put back together, fill with water, plug in, and go. You may need to wipe off the surfaces once in a while if you have hard water or salt in your tank - evaporation will cause deposits to form above the water's surface.

As far as pros and cons - I'm going to give you a link to another question where I already answered this in some detail:

http://answers.yahoo.com/question/index;_ylt=Al89g6ffh6eDwG8OZnltF4IAAAAA?qid=20070121142409AAqXmPT

Note that some people use the undergravel alone, some use the hang-on only, and other use both together, all with some degrees of success.

There's a lot of info to consider here - not just what we're telling you - but also your intent with what you're keeping in your tank. Good luck!

BTW - love the nickname!

Answer 2

Well, it depends on the type of fish really. But some pro's and cons to consider are:
You will have to vacuum either way
With the UGF you won't have to buy more filter cartidges, but with the over the back, there's less of a current.

Personally, what I did was I bought a pretty weak powerhead for my tank and set up my decor strategically so there was little current but the bacteria in the gravel got the oxygen and nutrition they needed, and then I got an over the back filter as well. But, I already had the UGF, so it wasn't too expensive to set up. But it's something you might want to consider.

Good luck with your tank.

PS, the P fish with four syllables is a Plecostomus.

Answer 3

YOU NEED TWO TYPES OF FILTRATION BIOLOGICAL AND MECHANICAL. Now Undergravel filters are great in a freshwater setup with plants they feed theroots becasue of the debris and waste make sure you do a 10-15% water change each week and 2 power heads in each corner for 75g or less and 4 for 125 and up. But if you are looking at New age filters they make Sand bed filters that hang on the back that run off a powerhead. Or even better Marineland makes a Emperor filter with Bio-Wheels they house the Bacteria for you. If you have anymore questions email me I will help and never overfeed a tank with undergravel filter and get little crabs or fish that sift the rock for food that gets oxygen and it is s complete community

Answer 4

U/G filters are old technology,they require regular maintenance,(vacuuming),plants don't do well in U/G tanks,however they are very energy efficient,once established(and maintained), they are reliable and serve as a good back-up to another filter system. I have some tanks with U/G and some without. I would not rely on an U/G as the sole source of nitifying bacteria, by they can be reassuring to have as a back-up system. Hope this helps.----PeeTee

Answer 5

under gravel systems are much better than filters that hang on the side of the tank,as they clean the tank much better and are the only negative point is that its hard to clean them,the whole tank is to be emptied for cleaning the filter,it requires regular cleaning every 3 moths and its tiresome,but the pros over weigh the cons and u should go for it..

Answer 6

Most of my tanks have UGF's in combination with either a power filter or a corner (box) filter. You can't beat a UGF for biological filtration.
If you are lazy, a UGF is not for you. You really should do 20% water changes weekly with them, perhaps 25-30% if you do it every two weeks. Certainly not longer than every two weeks.
I remove or pile the gravel to one side for a semi-annual cleaning directly to the plate. It is amazing to see what filth comes out, even though I draw a fair amount from the up tubes with regular cleanings.
With the effort, they are great. If you are not willing to do the work, forget about them.

Answer 7

it rather is a controversy of what you desire to do. I even have them in maximum of my tanks. it rather is my in elementary terms filtration in a pair of them. The tanks that i do no longer use the UGF, have sand for a substrate. it is not correct in case you employ one or no longer, you will nonetheless ought to bathe the gravel each and every so in many circumstances. I even have powerheads related to all of them different than for my 5 gallon and fifty 5 gallon tanks. the single is in elementary terms a splash small for a powerhead, and the fifty 5 has my Angels in it. i be attentive to i will probably get griped at for this, yet in the tanks that I even have the UGF in, i in my opinion never vacuum the gravel. I even have those cone snails(do no longer undergo in strategies what they're) in the tanks, and that they do a exceedingly sturdy activity of preserving the gravel clean. The goldfish that I even have in the tanks additionally help. That seems to be their favourite pastime. They love digging with the aid of and cleansing the gravel. (sure, i be attentive to you all say that goldfish desire chilly water, yet mine are the main lively fish in the tanks) in case you have an UGF, you ought to use the two the airstones, or a powerhead. this is as much as you. They the two do the comparable factor, flow the water in the direction of the filter out plate, and flow the water throughout the time of the tank. Bubble wands are greater for adornment than the rest. My vegetation do merely fantastic with the UGF too. Like I suggested till now. this is in elementary terms a question of what you desire to apply. It won't harm something to have a UGF, except you're utilising sand. Then this is greater project than this is rather worth. the two way, it is not a foul theory to get a dangle on(like the Whisper) or a canister filter out additionally.

Answer 8

My last tank had an under gravel system that I did not clean for over a year. A couple little cat fish or a (starts with a P and has 4 syllables) to clean the stuff and don't over feed. Good air flow and steady temperature and you will have good little ecosystem going on.

Answer 9

Ditto to copperhead, dead on target as usual. I would only add that under gravels can be run continuously in the reverse flow manner. They will do no mechanical filtration that way, but still do a good job of biological filtration. You should only do this if you also have a hang on the back power filter in my opinion.

MM

Answer 10

My personal opinion, based on 35 years of fish keeping, is why would you want a septic tank in your fish tank? That's essentially what an under gravel filter does for your tank.