Is my sponge filter working?

  • #1
This is my first time really setting up an aquarium and I wanted to use a sponge filter to have low water movement. However, I have no idea how sponge filters work, or if mine is working. I’ve placed an air stone in the sponge filter, connected an air tube to it, then connected that to an air pump. There are bubbles coming out of it, but how would that be filtering anything? These are probably silly questions, but I just want to make sure I’be got it working correctly.

  • #2
It should be working. Lift the tube while it's running slightly out of the water and the amount of water that spills over is the equivalent to the amount of water that flows through the filter.

  • #3
Sounds like it is working to me.

The more air, the more lift created in the lift tube.

Sponge filters don't create a lot of flow, unless you have a good sized airpump. This is normal. Most sponge filters move water slowly.

Pull the sponge filter up toward the surface, so only a 1/4" of the lift tube is sticking out of the water. You will see water + air bubbles flowing out of the lift tube.

Let it run a few days, and you will start to see detritus and uneaten fish food collect on it.

How large is the fish tank, what sponge filter are you using and what air pump?
  • #4
As I understand it, when the air bubbles go up water goes up with them. This water is pulled through the sponge.
  • #5
I am awaiting my sponge filter bc the first I got was too large but I have a pre filter sponge and the stuff that attaches so quickly?!! How do I remove the tiny stuff that attaches. Squeezing it doesn’t help.
Marijn Lange
  • #6
Sounds like it is working to me. You can also hold a piece of paper (plain paper, not a newspaper as it contains inkt) or something stringy in front of the outlet to see if there is any movement.

A sponge filter uses air to pull the water up, the waters enters thought the sponge. That way debris and other stuff get sucked toward the sponge. There is an easy way of cleaning a sponge filter without losing to many beneficial bacteria and without making to much of a mess. Grab a bag and put it under water so that the bag fils up with aquarium water. Then go near the sponge filter and take the sponge of the filter and put it in the bag. Take the bag out of the aquarium and place it in a bucket (this is just to keep the floor dry, don't let go of the bag). Put your hand in the bag an squeeze the sponge, the water wil probably turn brown. Empty the bag and fill it with some new aquarium water and give the sponge another couple of squeezes. the water will probably turn brown again but that is fine. Then put the sponge back on the filter and you're done!

This is also explained in the following video (4:45)
  • #7
I am awaiting my sponge filter bc the first I got was too large but I have a pre filter sponge and the stuff that attaches so quickly?!! How do I remove the tiny stuff that attaches. Squeezing it doesn’t help.
I squeeze my filters as much as I can but eventually I just spray it from a hose with real pressure ..
You could try slapping it on the side of the bucket ..
You might be surprised how much gunk is in there and how much comes out ..
From Dr. Stephan Tanner of Swiss Tropicals;
Q: how do rinse Poret® foam sheets?

A: the easiest way is outside in the yard or driveway using a garden hose. Simply bang the sheet flat on the ground several times (Note: I recommend not wearing your best outfit doing this) to shake out the filter sludge, then rinse with the hose; repeat until the water coming out is relatively clean. Don’t overdo it! Sufficient microorganisms will survive this procedure to quickly re-establish the biology of the filter. It does not matter if you use cold or chlorine-treated water! The often repeated notion that this process would kill all the filter organisms is complete nonsense, because the residual chlorine concentration in drinking water is way too low to kill them.
About Dr. Tanner ;

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