Sealed room... Waiting my time?

[MedicalMike420]

I thought it was my fan like people suggested but it's not. If the had read the full post they would know that was the first thing I tested. I also went over it with new semi rigid ducting and went over everything in leak seal. (Rubber spray paint). I put that weather strip stuff I the door but it's still sucking in air. If I hold I lighter to a crack indoor it sucks that flame in whether my inline is OFF or ON. I really don't get it I spent $100 to seal it and I seem to have waged my money. There are some screw holes in the walls from hanging things I'll patch them up but I doubt they are the problem.
The room is sucking in air from my room which means it's losing air somewhere else I think.
Why is it still doing this after being sealed off?
Is it fans or air pumps? I have a rdwc in there

 

[coldcanna]

Shut off any oscillating fans and light a stick or 2 of incense, that will make its way to wherever the sucking is coming from. Are there any registers from the central ac/heat in the grow room or the room next to it?