Need Help With Ventilation

Hey, having some serious problems with bringing in fresh air. I have had my veg room running perfectly for about 3 weeks, air flow was great, no problems at all. I was getting my flower room ready and hooked everything up when the real air flow problems started.
I have white visqueen plastic on walls, there is so much suction that it is pulling the plastic off the walls(air getting behind plastic somehow too), it was just doing it to my flower room(not running yet), now its starting to effect my veg room. All 6" ducting, everything sealed with TUCT tape, then white duct tape over it.
I have a drawing of how my setup is laid out, I have a couple pics of flower room, will put veg up later. I need to get the flower room up and running this weekend, I have a couple of monsters ready to go!!
Sorry pics are shitty I only have a camera on my phone.

Here is my veg room pics

the obvious response would be you have too much negative pressure inside the cab. you can fix this by decreasing the exhaust (probably not what you want), increasing the size of the intake hole (must be larger than the exhaust) or adding a fan to the intake.