Alright who's HVAC up in the hizzy?

I've got a 3x3 and a 4x8.
6" cloudline fan
6" carbon filter
6" raxial can fan
6" ducting
4" ducting
2x4" to 6" duct y joint

The 3x3 is the veg tent. I top vent with 6" ducting to the 6" raxial inside the 4x8 and it just dumps the air. 2 floor screen vents open on the 3x3 and a 4" duct from bottom of 4x8 to bottom of 3x3. Just passive on that. Closing it up gets a slight pull on the sides.

The 4x8 has the 3x3 whatever top of the light air dumping into it on one end from the ceiling. Blows towards the filter which is 7 feet away. And here's where I have temp issues in the large tent. I've got floor and an oscillating fan at canopy height blowing away from the carbon filter towards the raxial hoping that it creates a circular air exchange with the heat.

Now the veg tent 3x3. I could just passively exhaust the air from it or just use tiny clip fans. If I remove the intake from the flower tent and just have the exhaust into it. Figure out how much screen flap I can have open to have neg pressure still and keep temps/rh.

This would remove the raxial from that section. I could then get a second 6 inch filter. Or could I go big like 8 or 12 inch filter and have the raxial first pulling through the filter, then the cloudline after? It's about cfm yea?

I'd add one more fan maybe

6in cloudline on top of 4x8 with intake opposite bottom with 6in axial . The filter could be restricting the air flow if it's clogged with moisture. To tell if this is the issue simply test heat buildup with it on vs off You can drill the rivets out and remove the charcoal and bake it. I'd have some sort of filter preventing dust build up in the filter

Then 3x3 tent with just circulating fans with the front left open

The real fix is most likely getting an 8inch cloudline 8x4 is a lot of tent. Going with a 2nd 6inch would work too but then you might have to get another filter

What about setting up your ventilation independent for each tent? Maintaining a good 3x3 veg environment on the same ventilation with a 4x8 flower tent will require compromises. Veg temp and humidity dial in differently than flower temp and humidity. And two six inch fans for a 3x3 and a 4x8 seems a little light on cfms.