Help with Skimmer Setup Please

My cycle is finishing up and I want to add the bio cube skimmer to my 29 gallon cube.

1. It shows it being attached to the area where the carbon fiter was. I guess I dont need that anymore? Or could I use both?

2. What is the point of the check valve? I had to remove this because it wasnt allowing any air to flow. Is this correct?

3. What level should I make it bubble at? I had it bubbling right at the top of the reaction chamber but no bubbles were making it to the collection cup. When I increased the bubbles with the air flow valve the collection cup would just fill up with water.

Thanks for your help!

 

If the check valve wasnt letting air through it was backwards. It would be used to keep water from syphoning out of the tank and through the pump in the even of a power failure.

Keep the bubbles at the top and let it breeak in. once it gets a little dirtier the bubbles will make it father up and into the collection cup.

 

I swear it was on in the correct direction. I couldnt get air to blowout either way. Defect?