How do air/sponge filters work?

[Kiro]

I've seen breeding tanks with a single sponge filter. My question was: how do they work?

I know you have to feed a line from an airpump into them.. Is it the water displacement from the air that sucks the water through the sponge?

Also, could I make a bigger sponge and put something like Sera Siporax inbetween the sponge and the air tube? I suppose I'd need a heavier air pump, or would the filter be too big to be used with just air?




EDIT: Ahh, google is our friend. I found a diagram explaining the function. Still, my second question stands: Could I use a bigger sponge and fill it with more media?

[kaceyo]

If you want to use media like siporex it would make more sense to use it in a filter that would use it more efficiently, like a canister or even an Aqua Clear HOB.
Sponge filters are intended to be simple, easy maintenance bio-filters for basic setups, like breeder tanks and hospital tanks.

[Foxfire]

For bacteria that process ammonia or nitrite the flow rate and oxygen level are critical - air pushing water through a sponge provides both. Such a setup would do very poorly for a ceramic noodles - that is why canister filters use powerful water pumps; HOB filters - esp. biowheels tend to provide a lot of air exposure so flow rates can be lower.

That is my take on the subject.

[Kiro]

Okay, Thanks guys

I was just wondering how to increase the amount of filtermedia in smaller breeding/growout tanks that use an air/sponge filter.

Guess I'll just use a bigger sponge... or maybe fill a hamsterwheel with bioballs that rotates automatically at the water's surface?

[jeff@zina.com]

I was just wondering how to increase the amount of filtermedia in smaller breeding/growout tanks that use an air/sponge filter.

Bigger or more sponges.

In general, a sponge provides the most filtration surface of any media. Ceramic rings are actually quite low in surface area, their advantage is they don't clog up.

Jeff

[Kiro]

Bigger or more sponges.

In general, a sponge provides the most filtration surface of any media. Ceramic rings are actually quite low in surface area, their advantage is they don't clog up.

Jeff

I had no idea, I always thought these things were designed specifically to have as much surface area as possible

[mathao]

Okay, Thanks guys

I was just wondering how to increase the amount of filtermedia in smaller breeding/growout tanks that use an air/sponge filter.

Guess I'll just use a bigger sponge... or maybe fill a hamsterwheel with bioballs that rotates automatically at the water's surface?

yuo could just put it all in a meshbag and let it sit in the tank, that works too. then when you need to move it, just take out the bag and put it in another tank. easy and simple.

[Willie]

Double stack your sponges so they take up the same footprint with double the capacity.

[AndrewB]

Being a science teacher I have to jump on this thread and give you more info then you want.

Although I've never read this in a textbook I would imagine that sponge filters work by a physics phenomenon known as the Bernoulli's principle. This principle basically says that when the velocity of a fluid (in this case aquarium water being pumped up with a bubbler) increases then the pressure around it decreases. The water surrounding the sponge filter is then pulled from a area of relatively higher pressure outside the sponge to an area of lower pressure inside. The debris is pulled into the sponge with the water flow.

[Kiro]

Being a science teacher I have to jump on this thread and give you more info then you want.

Although I've never read this in a textbook I would imagine that sponge filters work by a physics phenomenon known as the Bernoulli's principle. This principle basically says that when the velocity of a fluid (in this case aquarium water being pumped up with a bubbler) increases then the pressure around it decreases. The water surrounding the sponge filter is then pulled from a area of relatively higher pressure outside the sponge to an area of lower pressure inside. The debris is pulled into the sponge with the water flow.

So there's a hole in the water due to it being moved up by the bubbbler, and now new water will fall into the hole from all sides. gotcha!

[Jennie]

you can also use a power filter pump with sponges. I do it both ways