3 tents 2 fans need help setting up with cooling from winter air

I have 3 tents in one bedroom. 1 veg with 600 watt lumatek with a MH bulb and 2 flower tents with 1000 watt lumateks with HPS bulbs. All three reflectors are exhausted with 1 6inch inline fan and it goes from reflector to reflector through the tents up to the veg tent which one end of the reflector is bare and has suction from it bc its at the end on the line. This is all exhausted into the attic and has a carbon filter on the end pushing air through it. The veg tent stays cool from the negative pressure and fresh air from the room that it is in because its at the end of the line, the flower tents never had this negative pressure since the exhaust from the fan goes right through the tents with ducting to the next reflector. so during the summer months i run a 14K btu dual hose air conditioner with ducting to each of the flower tents and this keeps my temps perfectly at 78 if i keep the ac on 76, even when its 90 outside in the summer but it also creates a positive pressure and i don't believe its changing the air in the tents as i would like. So now its getting colder here in new england and instead of cooling the two flower tents with this ac i wanted to use the cold air from outside for free to cool them. So i bought another 6 inch inline fan and a CAP day/night temperature control unit with hopes of drawing fresh air from outside into both of my flower tents. Now that i have it and i was setting it up i stopped and thought, now that i have 2 6inch inline fans and 1 inline duct booster should i reconfigure the whole thing so i have negative pressure in all 3 tents then try to just cool the whole room with the duct booster and the temp control unit? How would any of you professional or more veteran growers set this up?? Also 2 tents are on one side of the room and another one is on the other side of the room, so they are not and can not be all in line with each other i don't have the room for it.

i have 3 5x5 tents
2 6inch active air inline fans 400 cfm
1 6inch duct booster i think somewhere around 170 cfm under load
1 speed controller for a fan
1 day/night CAP temperature controller
1 carbon filter
2 magnum xxxl air-cooled hood
1 daystar air-cooled hood
plenty of ducting to do whatever

Please someone, anyone im open to all suggestions! how would you set this up ducting and cooling wise?

And if anyone was wondering, this is a licensed legal medical grow.

Get on MS Paint and draw up a small sketch of your configuration. It is hard to piece together through your description even though I have a general idea. You also need to tell us how far apart these rooms are, including all pertinent information on the diagram. Fan, CFM, length of ducting, size of room, temperature of air being pulled into the house, temperature and environment of all grow rooms.

I know its ugly drawing but.....ambient temp in the room all 3 tents are in is usually 70F with lights off and 80-85F with lights off. The blue ugly lines are 6 inch ducting flowing the direction of the arrows. The 2 tents on the left are about 6 inches apart and the back 2 is about 6-7 feet apart. The tents are 5x5x7 sun huts. the flower tent on the right has a 6 inch active air inline fan 400 cfm blowing up into the attic, and it sucks in from the other 2 tents through all the aircooled hoods. Everything is fine with the ac but i just bought another 6 inch active air fan and a CAP temp controller to try to cool the tents by sucking air in from outside through a hepa filter so i can shut the ac off for the winter. im just trying to set it up right so the air in the tents gets changed properly and im confused and dont know what the best route would be

As300zx27 said:

View attachment 2852168
I know its ugly drawing but.....ambient temp in the room all 3 tents are in is usually 70F with lights off and 80-85F with lights off. The blue ugly lines are 6 inch ducting flowing the direction of the arrows. The 2 tents on the left are about 6 inches apart and the back 2 is about 6-7 feet apart. The tents are 5x5x7 sun huts. the flower tent on the right has a 6 inch active air inline fan 400 cfm blowing up into the attic, and it sucks in from the other 2 tents through all the aircooled hoods. Everything is fine with the ac but i just bought another 6 inch active air fan and a CAP temp controller to try to cool the tents by sucking air in from outside through a hepa filter so i can shut the ac off for the winter. im just trying to set it up right so the air in the tents gets changed properly and im confused and dont know what the best route would be

Click to expand...

I would probably test a few configurations, but one that hits me right off the bat is taking the VEG tent off the circuit of ducting. I would simply allow the VEG tent to exhaust into the room, I would blow the A/C into the room, or the cold winter air into the room, then simply leave the two 400CFM 6" fans on the two FLOWER tents. Those two flower tents will now be pulling air from the room, and exhausting into the attic. As opposed to trying to maintain pressure between all 3 tents, this would allow a substantial increase in pressure pulling just from the two FLOWER tents, in my estimation. Does this sound like a possibility, or something you thought of but something kept you from executing it?

i dont have enough fans for that at the moment.....or did you mean setting it up like u said without venting the veg 600 mh?