Fans for venting 4k, as well as air for sealed room.

So I'm still debating how to vent this setup best.. I just wanna be sure this will work. I'm doing 2 8x4 trays under 4k.

My dilemma is that I'm not sure if I should go two 8 inch inlines doing 720cfm each.. One before Y adapter, and the other on the other side closer to the other. I'm trying to get the fan position as efficient as possible ideal.

On one side the hoods are 6 inches, is using 8inch fans okay? I was going to just go from 8 inch ducting to 6in when I hit the hoods.

My other question is, do I need to install some sort of intake? I plan on this room being completely sealing, only air the leaves room is whenever door is opened, or when the filter fan is going.

Any suggestiosn would be GREATLY appreciated.

That seems fine to me. You can either intake air from outside to cool your lights and vent it to the outside, or you can simply have 1 exhaust which sucks air from the grow room, through the lights, through your filter and out. Either way wherever you exhaust air you will need an intake too (but not necessarily an intake fan, passive is fine).

I don't know if I fully understood your question, sorry if the answer isn't what you are looking for. Also, you must always have air flow within your grow room when the lights are on or you must add CO2.

since your sealing the room i assume your going to use co2. the 8in will be fine for cooling the hoods but you need to pull n discharge outside the room n make sure all seals are tight n leak proof. the diagram shows unbalanced lengths on your venting runs, they need to be even lengths from y to hood to have a balanced cooling to all hoods. sealed means no venting, during lights on anyway. the scrubber should be run on its own fan inside the area n not vented outside, that way it cleans the air but doesnt dump the co2. you can exchange room air lights off with no prob as you arent using co2 lights off, but if you are concerned about smell you will need to add another scrubber to the exaust set up. passive is fine just have a dampner on so you dont loose co2 during non opp of venting set up. fans cerculating room air is a must just so you have movement inside the room always, so a couple wall mounts or floor fans will be needed. usually a sealed room needs an ac n dh unit to help keep environment in optimum conditions. good luck, hope this helps...JMO

This room wont be CO2 yet, I want to get everything else good before I start it.

I'm trying to figure out the best way to cool this room with venting that is separate from the room, using my two windows, which aren't placed ideally. There is no way I can make the runs even, one side is always going to be around 5 feet shorter. Would it be better ot just get a massive 10 or 12 inch fan sucking the air for the whole system? Or would two 8 inch inlines doing 720 each be okay if they are placed well? As for intake I was just thinking of installing a backdraft damper(with filter running on opposite end to open it), plus the room door will get opened fairly often at least a couple times a day.