lightproofing between cabs in 1 closet??

Right not i just have my flower room in the closet, i have another rubbermaid box that i veg them in. I am going to use some of the extra room in the closet and put another shelf in there and transfer the vegging stuff into there, what my question was is how are you guys light proofing in between cabs? I have 4 abs elbos in the bottom of my current flower shelf, and i can still see light under the door at night, my fear is that the light will leak into my flower room causing hermies! So if anyone that has done this sucessfully please giuve me some advice thanks!

I use a closet that is divided vertically by a fixed shelf. I have an exhaust fan in the upper bloom section and passive intake at the bottom of the lower veg section. A passive vent allows air to move from veg to bloom, with black plastic stapled to the shelf and back wall above and below the hole to block light (basically the same idea as using PVC elbows painted black inside - the result is two triangular 'tubes' - one above the other and connected at one end by the hole in the shelf if you follow the idea) The shelf hole is located all the way at one side, and the openings in the plastic where air enters/exits are about midway across the back wall.

The shelf is flush with the front of the closet, so I have a 6 mil black plastic curtain over the front of each section with velcro around the perimeter to create a seal. Access to either section is by pealing back these light curtains.

The closet I'm using used to have three drawers down below and two vertical 1/2 width doors up above. The upper section had movable shelves - one has been left in place as a light support which I can raise or lower as needed.

Because i am lacking in floor space i want to stack the areas. I am thinking i can use the 3" Black abs elbows i have (one at each corner) and connect them with a piece of pipe with enough holes in it, and maybe cover it in nylon to block some more light if necessary.