Troubleshooting sponge filter

[Jim Sinclair]

I have an Aquaneat sponge filter in my convalescent tank for injured fish. Tonight I came to do a water change and found that the filter was not working. The pump is plugged in and running. If I disconnect the airline tube from the filter and hold it under water, it bubbles vigorously. But when the tubing is reconnected to the filter, there are no bubbles.

I took the sponge off the filter and rinsed it in a bucket of tank water. I examined the plastic inner core for clogs. It looks all clear. I can hold it up to a light and see light shining through the central tube where the air is supposed to blow through. But when I connect the airline tube to it, still no bubbles. Even with just the plastic core underwater and the sponge not on it, there is not a single bubble.

So my most fragile and vulnerable fish are not getting any filtration or aeration. Can someone please help me troubleshoot this?

 

[Colin_T]

There will be some gunk in the plastic fitting that the airline goes in. You need to check it thoroughly and clean it. If you can't find the blockage then try blowing air back the other way. Basically disconnect the airline and try blowing air through the filter but in the opposite direction to what it normally goes.

 

[Jim Sinclair]

I did check it. I held it up to a light and looked through it. I poked a long tweezer end into it. No improvement.

 

[Colin_T]

The blockage is usually in the fitting the airline joins onto. At the bottom of that fitting the plastic usually has a curve and a small hole that lets air go into the clear tube. The blockage is normally in the small hole where the air goes into the clear uplift tube. You will have to keep looking but it will be there.

 

[Jim Sinclair]

Do you have a picture of what you're talking about? It doesn't sound like anything I see on the filter that I have.

 

[Colin_T]

The blockage is normally inside the fitting where the small yellow dot is on the picture.

You will have to remove the clear tube and the T-piece tube that joins to the filters. Then you should be left with the plastic bit that the airline attaches to and the clear tube goes in. Once you have that piece, shine a torch inside it and there should be a small hole and that is where the blockage normally occurs.

You can test that piece by attaching the airline and putting it in the water. If the blockage is in that bit then it won't blow any bubbles.

 

[Lajos_Detari]

Hi Jim,
Can you take a photo of your sponge filter?
Usually there are a few possibilites:
1)The joint parts have become loose or choked.
2)The sponges have accumulated too much debris.
3)Air tube connection to the air pump is loose.
Or the air tube is broken/deformed which will block the air from flowing through smoothly. Change the air tube.
4)Did you use air pump "valve" to protect your air pump by preventing the aquarium water from flowing backward during power outage? If yes, try to remove the valve.
5)Check your air pump to ensure that it's still working.

 

[Colin_T]

In the OP's first post he says the pump is running but I am thinking that if the filter isn't blocked, then maybe the diaphragm in the pump might have split. This can be tested by putting the airline at the bottom of the tank. If bubbles come out of the airline when it is at the bottom of the tank then the diaphragm is good.

Split diaphragms will normally cause the pump to make more noise.

 

[Jim Sinclair]

Thanks for the clarification. That's not the same filter I have. Mine is this kind: https://goo.gl/images/CgVYmZ

And the hollow center of the plastic core of my filter is straight, with no bends, and it's very easy to shine a light through it, or just hold it up to the light and look through it. I see light when I do that. I don't see any blockage.

The blockage is normally inside the fitting where the small yellow dot is on the picture.

You will have to remove the clear tube and the T-piece tube that joins to the filters. Then you should be left with the plastic bit that the airline attaches to and the clear tube goes in. Once you have that piece, shine a torch inside it and there should be a small hole and that is where the blockage normally occurs.

You can test that piece by attaching the airline and putting it in the water. If the blockage is in that bit then it won't blow any bubbles.

 

[Colin_T]

check the following link on youtube. It shows the same style of filter you have. Completely disassemble your filter and look for gunk. It is either blocked up or the air pump has issues with a diaphragm or flutter valve in the air chamber.

 

[Jim Sinclair]

I just posted a link to a photo of the kind of filter I have. Earlier I tried to take videos of what happens when I put the air tube in the water unconnected to the filter (vigorous bubbling) vs. when I connect that same air tube to the filter (absolutely nothing). That attempt led to an interruption in my efforts to troubleshoot my filter, as I stopped to call AT&T customer service and tell the tech support department that my phone is possessed and I need help to exorcise it. This is just not my night.

I pulled an airstone out of another tank and put it in the convalescent tank for tonight. At least there's water moving now. Later, if the roads and my driveway have been plowed, I'll try to take the filter to the LFS for assistance. It's 3:37 in the morning now. I'm going to bed.

Hi Jim,
Can you take a photo of your sponge filter?
Usually there are a few possibilites:
1)The joint parts have become loose or choked.
2)The sponges have accumulated too much debris.
3)Air tube connection to the air pump is loose.
Or the air tube is broken/deformed which will block the air from flowing through smoothly. Change the air tube.
4)Did you use air pump "valve" to protect your air pump by preventing the aquarium water from flowing backward during power outage? If yes, try to remove the valve.
5)Check your air pump to ensure that it's still working.

 

[Jim Sinclair]

Bubbles do come out of the air line when it's in the tank. I don't know if I pushed it all the way to the bottom of the tank, though. That will be something to check in the morning. Thanks.

In the OP's first post he says the pump is running but I am thinking that if the filter isn't blocked, then maybe the diaphragm in the pump might have split. This can be tested by putting the airline at the bottom of the tank. If bubbles come out of the airline when it is at the bottom of the tank then the diaphragm is good.

Split diaphragms will normally cause the pump to make more noise.

 

[Essjay]

I have a similar sponge filter in my betta's tank - mine is an Aqua One.
With mine, the rigid parts come apart. The inner core pushes into a short section with a disc full of holes across the middle, and this pushes into the base. When the bubble rate starts to slow, I have to dismantle the core and base to access the short section, then scrub the goo off the holey disc with a fish-only toothbrush and finally poke a pin through the holes to get rid of the last traces of goo.
Does yours come apart like this?

 

[Jim Sinclair]

In the OP's first post he says the pump is running but I am thinking that if the filter isn't blocked, then maybe the diaphragm in the pump might have split. This can be tested by putting the airline at the bottom of the tank. If bubbles come out of the airline when it is at the bottom of the tank then the diaphragm is good.

Split diaphragms will normally cause the pump to make more noise.

YES! It was the pump, not the filter. After I got a few hours' sleep, it occurred to me to try taking the tube out of the bubble wand I'd borrowed from a larger tank to put in there, and plugging it into the filter instead. It works!

So this evening I went to the LFS and got a new pump so the fish in the big tank can have their bubbler back, and some new airline tubing because the old tubing has become stiff and rigid and doesn't want to stay on.

And my as-can-be-afforded wish list now includes another new pump (unless the one with the split diaphragm can be repaired?) and another bubble wand for the convalescent tank, because Adrien, my eyeless fish, seemed to like swimming around and through the bubbles.

Thanks for the help!

 

[Colin_T]

Diaphragms can be repaired cheaply and easily. You simply buy a replacement diaphragm for that specific pump and swap it over.

Turn the air pump off and unplug it.

Turn the pump over and look at the bottom of it. On the bottom of the pump should be 4 or 6 small screws that hold the case together. Undo these screws and separate the top and bottom halves of the pump case.

Inside the pump will be a coil (a couple of thin metal plates with some copper wire wrapped around it. DO NOT TOUCH THIS because it will be hot and if there is power going to the pump you will get zapped.

Inside the pump will be a metal L shaped arm with a magnet on the end. The magnet will be next to the coil. This L shaped arm is attached to the rubber diaphragm. You need to remove the L shaped arm and diaphragm together. They are sometimes held to the case by a screw and sometimes the metal arms simply pushes into a rubber grommet.

Once you have removed the arm and diaphragm you separate them from each other. Check the diaphragm for holes, tears, splits. Take the diaphragm to a pet shop and get a new one that is the same height, thickness and diameter as the old one. Check the diaphragm for squishiness too. Sometimes the rubber is harder or softer than it should be and they don't work properly. I usually buy a couple of diaphragms just in case one is dodgy.

Put the new diaphragm on the L shaped arm.

The diaphragm fits onto the air chamber. The air chamber has a couple of small thin rubber flutter/ flapper valves that sometimes get holes in and this will also stop the pump from pumping air. Check the valves for holes. If they have any you will need to replace them. They can be bought from the pet shop.

Once the air chamber has been checked (and repaired if necessary), put the air chamber and diaphragm back together and put the L shaped arm back into its spot. Plug the pump in and turn it on. Connect some airline to the pump outlet and see if it works. If it does, then turn the pump off, replace the base and screw it back together and away you go.