Sponge Filters - EDUCATE me

[Diablos]

Hmmmm, I bought some small plecos one got in the filter and munched... I know many breeders use sponge filters when small fish are present.

So if you could educate me on how they work and suggest some brands, that would be great. FYI this would be going in a 10 Gallon tank. Thanks a ton.

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After some quick research, looks like these "Lustar Hydro-Sponge Filter" are the sponge filter. How are they powered... please discuse.

[gheitman]

I use sponge filters in most of my tanks, especially those I use for breeding. The sponges provide a great breeding ground for aerobic bacteria for filtering the tank as well as a good mechanical filter. I purchased some Azoo filters from Drs. Foster & Smith. I like them better than the ones you are looking at because it is easier to clean the sponges in my experience. In any case, the sponges are powered by an air pump outside the tank.

[Ben K]

I had a sponge filter and I didn't think it was working all that great. Sure, the sponge did get dirty and such, but just the appearance of it didn't seem like it was really working. I assume that the air is suppose to go through the sponge? Mine didn't appear to be doing that, coming out as large big bubbles rather then small filtered bubbles like I would have thought. What would a proper working sponge filter look like, bubble and filter wise?

[majolo]

Originally Posted by Ben K

I had a sponge filter and I didn't think it was working all that great. Sure, the sponge did get dirty and such, but just the appearance of it didn't seem like it was really working. I assume that the air is suppose to go through the sponge? Mine didn't appear to be doing that, coming out as large big bubbles rather then small filtered bubbles like I would have thought. What would a proper working sponge filter look like, bubble and filter wise?

No, the air doesn't go through the sponge. As I understand it, the air bubbles up through a central column (In the Azoo filter I've got going anyway), pulling water along with the bubbles. The setup is such that the only place where the water can come from is through the sponge, so the net result is a flow of water from outside the sponge through to the central column. The beneficial bacteria grow on the sponge's large surface area, and the water passing through is exposed to the bacteria. I believe it's a good biofilter, but not great for mechanical filtration, right?

[SparKy697]

No, the air doesn't go through the sponge. As I understand it, the air bubbles up through a central column (In the Azoo filter I've got going anyway), pulling water along with the bubbles. The setup is such that the only place where the water can come from is through the sponge, so the net result is a flow of water from outside the sponge through to the central column. The beneficial bacteria grow on the sponge's large surface area, and the water passing through is exposed to the bacteria. I believe it's a good biofilter, but not great for mechanical filtration, right?

You are exactly correct. Sponge filters are almost all biological, any mechanical filtering that happens is secondary.

I like to go a bit bigger than is needed for these filters
DR's Foster & Smith have a nice selection of sponge filters to choose from. If you are doing weekly PWC you can get by without a lot of mechanical filtration.

[Diablos]

So I have an air pump and I think its TO loud. Would this same concept work with a power head hooked up? If anyone is doing that please let me know how its going and the brand you're using.

[Sidi]

You don't necessary have to go to a sponge filter. You could put a prefilter on your current one that will prevent fish being sucked up. Many people use the sponge filter media, or something similar. Cut a hole down into it, then just slip it over the intake.

[Diablos]

Hehehe these guys are not getting in the intake they are swimming up the overflow

[mvigor]

Yes, you can drop a powerhead into the sponge filter's central column instead of using an air pump for uplift. The problem you might run into is finding a powerhead adjustable to a low enough flow rate for a 10 gallon tank.

[duke33]

Ultimatesponge.com has some real good filters and food.

[Gundy]

I hate to sound like a goob, but whats the difference between mechanical and biological filtration?

I was thinking of using a sponge filter for a crayfish house-10gal.

[SparKy697]

Think of mechanical filtration as a strainer or a screen that traps things you do not want in the water.

Biological filtration is the process by which bacteria is used to digest the ammonia that is created by fish and turn it into a less harmful form.

[Gundy]

So what is the bad when using sponge filters, that it won't catch the poo?

[SparKy697]

I think it's a matter of volume. Sponge filters will perform some amount of mechanical filtration, but the foam gets clogged up really fast. Their primary role is biological filtration.

You tend to see them used a lot in breeder tanks because they will not trap or suck up the little ones.

[BrianNY]

Correct. The main function is biological filtration as the surface area in a sponge allows for increased colonization of nitrifying bacteria. They are great in fry tanks because they handle the increased bioload as the fry grow. Mechanically they will collect solid matter and need to rinsed frequently in a bucket of tank water. With adaquate pwcs, it's the only filtration needed.

[gheitman]

I clean the sponges on my sponge filters once a week. I just gently squeeze the sponges out in water removed from the tank. You can tell after a long time that the sponge is becoming clogged up if it doesn't spring back into shape when you squeeze it out. At that point I replace that sponge with a new one (all of my filters use either two or four sponges so I only decrease my colony of bacteria by half) and then thoroughly rinse and dry out the old sponge. It can be used again later.

Sponge filters are great for quarantine/hospital tanks because they don't filter out medications the way filters with carbon will do. I like sponge filters because they are cheap, simple, reliable, easy to maintain and the surface of the sponge provides an excellent feeding ground for fry.

[duke33]

good tip

[gheitman]

I forgot to mention in my earlier post that I use sponge filters in 7 of my 9 tanks (all of them 20 gallons or less). As far as recommending a brand goes I like the Azoo Oxygen Plus Bio-Filters (models 2 and 3) that I get from www.drsfostersmith.com. I prefer them over the Hydro-Sponge because you can remove the sponge for cleaning without having to remove the whole filter from the tank.