What's wrong with my sponge filter?

Because there's no air coming out of it...

Are they all "T" off the same airline? You may have to use valves to adjust airflow to even things out.

Yes I've tried adjusting the lines, if I unplug the airline from the sponge filter that's not working air comes out of the tube. No matter which airline goes into that last valve, air never comes out. I'm thinking my pump isn't strong enough to get air to all the lines.

fishkeeper01 said:

Yes I've tried adjusting the lines, if I unplug the airline from the sponge filter that's not working air comes out of the tube. No matter which airline guess into that last valve, air never comes out. I'm thinking my pump isn't strong enough to get air to all the lines.

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That's because there's no back pressure or restriction when you unplug the line. Like I said get a few valves and splitters from petsmart for a couple bucks and you should be set!

I'm sorry, not to be irritating, but I don't quite understand.

And I put them on the two lines that are working? Also what is back pressure?

I'd put one on every line and play with the balance until all your sponges are bubbling equally.

Back pressure in this case is going to be any sort of obstruction or force acting against your airflow. In this case it's caused by your sponges and the difference in hose length between each one. As well as the water pressure pushing back against your airline.

This whole thing should be < 5$ to fix.

Yes put one on all the line and adjust them.until you get equal amount of bubble per filter. Best you can

Hanzorz at Verizon.net

But would it hurt to get a bigger pump?

It depends on what brand/model pump you have now.

How many filters are you trying to run? Are you using air stones in the sponge filter?