Making a fuge

[Perthegallon]

So I want to make a fuge out of my ato I’m thinking about just getting a small usb pump to let it pump into it and letting the water over flow back into the tank. So the one question is how do I stop the macro alage from flowing it back into the rest of the sump?

 

[Perthegallon]

 

[Perthegallon]

anyone

 

[Redfoxtang]

Could cut some egg crate up and silicone it to the glass and then you could put a filter on the egg crate. Would be the only thing I could think of really without dismantling the ATO section and reconfigure. Maybe others have different ideas.