The Sponge Filter is a great tool in the aquarium hobby, so good that next time you walk into your local fish store pay attention to how many of their tanks use sponge filters…and there’s a reason for that.
A sponge filter is a pretty simple piece of equipment. It’s a filter made out of a sponge…that’s it. It has a cylinder column in the middle to allow air to reach the bottom of the sponge and it has a weighted base to keep it sitting on the bottom of your tank. All it needs is an air supply from an air pump and an air tube to attach the 2 and it works like a charm.
How Does a Sponge Filter…Filter?
So how does this actually filter, good question…The way it works is that air is pushed down into it, which is coming from your external air pump, it gets pushed down through the center to the bottom of the column.
This air then needs to find its way up and out of the water. As the air bubbles rise it sucks water into the sponge. The sponge then catches and traps particles floating around in your water, essentially filtering your water.
But as simple as that sounds, there’s a lot happening with a sponge filter…lets go over it .
- We already talked about trapping debris floating in your tank, so that’s your sponge filter providing mechanical filt
- ration. As it traps these loose floating particles it mechanically filtrates helping to clear up your water, something we all want in our tanks.
And speaking of clearing up your water, if you need more help with that I’ve written a Free Ebook with great tips and advice on how to get crystal clear aquarium water, you can Download It Free Here
- This added surface area of the sponge, along with the flow of oxygenated water through it, is the perfect recipe for the growth of beneficial bacteria. Good bacteria that you need in your tank will begin to grow on the surface of your sponge, just like it does on your bio-media inside your other types of filters like HOB’s or canisters. So that’s your sponge filter providing biological filtration.
Extra Sponge Filter Benefits
Air bubbles being released rise and pop at the surface of your water causing surface agitation. This surface agitation allows for the transfer of CO2 to exit your tank and oxygen to enter it. Oxygenating your water is essential for a healthy tank and happy fish. So that’s your sponge filter helping to oxygenate your water.
Are you keep track of all these benefits?, I told you sponge filters were great, but wait…there’s more…
This sponge filter isn’t tied down to anything in your tank, meaning its mobile…you can put it in a corner, move it to the other side, move it here and there…and like we already discussed it eventually will have tons of beneficial bacteria living and growing on it.
My point is, if you have an emergency and for whatever reason you need to set up another tank, for quarantine, or as a hospital tank, or whatever the reason…..this new tank can be instantly cycled by using your sponge filter from your main tank, which is already seeded with beneficial bacteria.
The bacteria on the sponge will be able to handle the bio-load from the fish in this new tank immediately….no waiting for the tank to cycle before adding in the fish…and trust me when this problem comes up, and it will come up while keeping fish, you’ll be glad you have something like a seeded sponge filter ready to pop right in!
Finally, this thing is like 10 bucks…and you most likely already have the air pump and tubes because you were already aerating your tank before right, I hope so….So for 10 bucks it cant be beat.
1 sponge filter can probably handle the bio load anywhere from a 10 gallon to probably about 40 gallons, depending on how many fish you have.
How To Clean A Sponge Filter
So how do you clean this thing? Super easy…fill up a bucket with tank water, you don’t need much, maybe a gallon or so, enough to fully submerge your sponge filter.
Then just dunk your filter in and squeeze out all the trapped dirt and debris. You’ll see your water get immediately darker which is good. Squeeze it a few times, just like you would squeeze your sponges from inside your filters during a cleaning.
And that’s it, sponge filter clean. Its super easy. And if you wanted to make sure it was extra clean you could have a second bucket of tank water and do the same process. After squeezing out the heavy dirt into first bucket then continue squeezing in second bucket to make sure you got it all out. Very simple…
Why use Tank Water to Clean A Sponge Filter
Now I do have to mention this because the aquarium hobby always has beginners coming in which we veterans appreciate everyday. The growth of this hobby and the expansion of knowledge benefits everyone and every fish!
The reason why you must do this in tank water is because your tank water is safe for the beneficial bacteria living on your sponge.
If you were to fill these buckets up with tap water from your sink, that water has chlorine in it, and the chlorine from your tap water that makes it safe for you and I to drink, will actually kill all the beneficial bacteria on your sponge.
You definitely don’t want that. Preserving your Bacteria is very important for keeping your tank cycled and your fish safe. Killing off beneficial bacteria can result in ammonia spikes that will harm or even kill your fish.
Cons Of A Sponge Filter
Now there is one common negative…I wont say negative I’ll just say a common complaint about sponge filters…The air bubbles popping at the surface makes a very annoying sound, maybe not at first, but eventually yes, it gets annoying.
But I have an easy fix for you…you can modify your sponge filter very easily by cutting out the center column and adding and air stone in the center. This air stone will break the bubbles up into much more smaller bubbles. These smaller bubbles wont make noise when they pop at the surface and you actually get more suction through your filter making it more efficient.
If you’d like a step by step tutorial on how to modify your sponge filter watch this video below!