I didn’t, I just cut to size, silver taped directly to the inside of the tent over the intakes, have some smaller pleated filters that will be in front of the materials and again silver taped to the inside of my tents, there is always a way!
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Freaking MacGyver over here! Do they block light?
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Don’t know yet but I use the passive intake covers that come with my tents and they do. In the past I have used cut straws directly in the Velcro for the closure of the intake going perpendicular to the strip of Velcro, on the outside of the tent, every few inches and sealed the Velcro around each one (10-20 of them per intake) and this is the only way to keep passive ventilation without leaking light IME.
There is only one vent that I need to worry about in my setup ( veg tent inside the flower compartment) whereas the pollen mitigation system is for my auto breeders in my lung room - not worried about light pollution there as everything in that room is on the same cycle
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Just gotta point out merv 17 to be n95 territory, think it was 19 to hit HEPA.
So if you’re really looking for HEPA like filtration you’re going to need a bit more material inline.
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How did your lightproof passive vent project go @Hephaestus ? When you started that I thought maybe I won’t have to use black straws in my intakes anymore 
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Haven’t had any noticeable light leaks… Just a 180° reversal. Haven’t tried a million candella and sensitive light detectors… Flat black inside was enough to take it down to good enough for the girls I go with.
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I’m a little late to this but a vacuum hepa filter isn’t very big and allow high air flow. May have to MacGyver a way to attach tho. I built my boxes with osb so I’m just gonna a quick mount to place over air intake on top of box
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thats what i bought from amazon 2 years ago, they were very inexpensive then there spendy now and not on amazon
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Nice unit. This whole thread gives me a business idea, I’m sure you can guess what it is lol
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Idea train.
Noticed this pic in my files and had to share. Some day I will cobble one similar. Wish I could credit the builder. Found here or interwebs.
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28x18x6" add flanges to bottom, drill intake holes in the lid… Then it’s just a flange to fit some 16x25 filters…
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Damn that’s pretty perfect. For simple budget, anyways. Wood or metal makes it last longer, but I do really like the grates.
I’m curious on your light blocker now, you have a link?
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More microgrow sized…
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Yeah… I was curious if it could be so simple as to make a long black tunnel essentially, with only 2 turns. Glad do see that worked for you, might do something similar.
My grow is only 3x3. Not tremendously big.
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Usually just the 180 with flat black interior is enough. At least that’s always worked for me.
But I haven’t gotten into tents in the middle of a room so far my intakes are always in unlit areas anyway.
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Oh, the basement is unlit at night and I’m blocking the windows, all pretty dark. But I’m adding a second tent, and better safe than sorry anyways.
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With two tents in a dark space only one needs to be lightproof 
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Better safe than sorry; I don’t trust my family 100% not to turn the basement lights on during the time I carefully schedule for dark periods so there is no reason to need to go down there…
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Just cut it to size and tape it over your intake.
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seen one similar on a woodworking page, guy made one t deal with sawdust,he used multiple 1" think furnace type filters
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