# Got a sponge filter for fry and it trys to float!



## Artsey (Dec 5, 2010)

How do I get it to stop floating? I had to put rocks on the bottom to stop it from floating up to the top of the tank. Anyone know what to do about it?


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## fmueller (Jan 11, 2004)

You need to squeeze it under water to get the air out.

If that doesn't do the job, please let us know what kind of sponge filter you have. They usually come with a stand to make them sink - for example the Hydro Sponge filters come like that, and they are a popular brand.










Photo from Jehmco, a place that sells these filters at a good price.

If there is no stand, a good option is to attach the foam to a tile (for example with silicone) like shown in the photo below.










I took the photo from Swiss Tropicals, which is a place selling very high quality foam.

Best of luck


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## Artsey (Dec 5, 2010)

Its a Seapora 136 and I did squeeze it but it still wants to float. It has a base just like the first picture you put up. It doesn't seem to be sucking up any matter from the tank either(very little). I thought it was supposed to act like a filter? I'll try to squeeze it again now and see if that helps.


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## Artsey (Dec 5, 2010)

Is the clear tubing that comes out of the top of the sponge supposed to be under water or above? I have it under the water but I was thinking maybe that is the problem. I tried it above too but it still floated so I'm at a loss. There were no instructions in the box. There was directions on the side of the box and nothing to show you what it should look like or what to do if your having problems...so annoying.


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## Guams (Aug 21, 2009)

Have you tried squeezing it several times to get as much air out of it as you can? I have the Hydro sponge filters (pictured above) and it took a few squeezes to get them to become a little more than neutrally buoyant. After a while they'll fill completely with water and sink on their own.

The tube should be under the surface of the water and they are not very good mechanical filters (for bigger gunk, at least). Sponges are primarily biological filters, so you won't see much gunk get sucked up. They do, however, do a wonderful job at keeping very small particles out of the water. Let it do it's job for a little while (a couple weeks) then give it a squeeze in a bucket of tank water. You'll see just how much small stuff these things do suck up.

Also, the more air you've got feeding the sponge, the more water will be pulled through. What air supply are you using? If it's underpowered you might not be getting good filtration.


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## jason081180 (May 5, 2007)

Artsey said:


> I thought it was supposed to act like a filter?


sponge filters do not have any moving parts so the only way it can move water is from the air bubbles going up the tube. this will never move much water. sponge filters don't work for keeping a tank clean they are more for fry tanks or for added bio filtering. they will do nothing for the mechanical filtering.


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## fmueller (Jan 11, 2004)

Artsey said:


> Is the clear tubing that comes out of the top of the sponge supposed to be under water or above?


Definitely under the water. You want to have at least half and inch to an inch of water above the very top of the clear tubing. That way the rising bubbles inside the tube will create a water current that leaves the tube at the top, and enters through the sponge at the bottom. If the top of the tube is not submerged there is no current, and the whole filtration effect breaks down.

Sponge filters are excellent for biofiltration, and it is easy to underestimate how much they do even for mechanical filtration. Granted, a sponge filter can never pick up large pieces of debris like a dead plant leave, but squeeze out a sponge filter after a couple of months in a tank, and you will be amazed by how much gunk gets trapped in those things that would otherwise be floating around the tank. A lot of breeders with hundreds of tanks in their fish rooms use nothing but sponge filters to maintain their setups. They are not the prettiest thing to put in a show tank, but very effective!


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## Glaneon (Sep 27, 2010)

Not to be silly.. but you did hook up an air hose to it with appropriate pump for the tank?


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## cjacob316 (Dec 4, 2008)

my sponges pick the small stuff out of the water, but they don't move the big stuff around, that just falls to the bottom, but it's really easy to clean up


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