# Undergravel Aquarium?



## ThePhoenix (Jul 23, 2012)

I heard something about these the other day and I am not sure I understand what their function is. Yes I know I could google it but I would rather hear from someone who knows what theyre all about.

Why is there an empty space under the gravel?
How do they work?
What do they do differently?

Thanks


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## sunshine_1965 (Aug 16, 2011)

Are you talking about the under gravel filter? What it does is pull all the debris down to the bottom of the tank and collect in the filter. I tried this many years ago and had a nice clear tank. What I did not realize at the time was how hard it was to get all the crap out of the filter. I would gravel vac my tank weekly and seem to get lots out but was not until I wanted to change the gravel did I realize how dirty my tank really was. I vacuumed the tank really good and started to remove the gravel. The filter lifted up a bit and my tank went real dark and dirty fast. I quit using that type of filter that day. Took me a couple of hours to get my tank back to an acceptable clarity without starting all over again. Some people use them and would use nothing else but them. Good luck in this research hope you get many different types of responses so you can make an informed decision.


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## ThePhoenix (Jul 23, 2012)

Did yours come with a powerhead in the corner that blew out water sucked down from the bottom?

Are these types of filters available for any size tank?


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## sunshine_1965 (Aug 16, 2011)

You have to buy the power head separately but yes. I had mine in a 90G I am not sure how big they make them for.


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## Elle (Oct 25, 2010)

Undergravel filters draw water down and trap crud underneath the filter on the bottom of the tank. They are pretty nasty...a lot of crud gets sucked into them and they can act as breeding grounds for ammonia, and disease, especially with dirty fish. You have to rip the whole tank apart and remove the substrate to clean under them. I had one in my very first tank and wouldn't ever use them again.

The Undergravel Filter Controversy

Undergravel JETS on the other hand, are way cool and help keep the surface of the substrate clean by blowing crap to the filter intakes. Constructing Under-Gravel Jets


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## djamm (Sep 25, 2010)

Under gravel filters are not generally as good for filtering as HOB (hang on back) or Canister filter....It is a hold over from the way you used to filter from the 1970's, along with those corner filter boxes were both driven originally by an air pump. Not generally recommended compared to other filtration options....I would go for a sponge filter any day over one of these. Typically we use both HOB and Canisters on most of our tanks...


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## Immus21 (Jun 14, 2010)

The first tank I ever bought was supposed to come with one but I refused to buy the setup unless they exchanged it for a canister filter. As already stated they are hard to maintain and just hid the detris etc. I would never recommend using one.


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## The Guy (Nov 26, 2010)

I would not recommend using one, the only way to clean the crud collected in them is to tear your tank down PITA!! As mentioned by Drew go with a large sponge filter or a big HOB.


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## macframalama (Apr 17, 2012)

they are horrible, pointless, dont work with sand. and overall wackadoo...


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## ThePhoenix (Jul 23, 2012)

ok thanks guys. wasnt planning on buying one, just wasnt familiar with them


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## macframalama (Apr 17, 2012)

When your friends start talking crazy you have an intervention right away lol


ThePhoenix said:


> ok thanks guys. wasnt planning on buying one, just wasnt familiar with them


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## ThePhoenix (Jul 23, 2012)

hehehe... my MTS is maxed out at 5. I have no more room for tanks, and no more power outlets


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