25 feet!!@!
Yea that fan is way under powered to push the air that distance
I'm sure ur tent is around 120 cf, your fan pushes 188 max, that's with no restrictions like 25 feet of duct.
To run that distance you are going to need at least 400cfm

FuqStik said:

And I feel no change when I close the tent

It's venting to my downstairs... so it's like 25 feet of ducting. does that make a difference?

Click to expand...

It makes a huge difference.
Here's an example to calculate loss from ducting and filters:

Jermamma420 said:

It makes a huge difference.
Here's an example to calculate loss from ducting and filters:

Grow Room Fan Size Calculator with Size-wise CFM – What for Me

whatforme.com

Click to expand...

If this is correct, it boils down to this:

Rule of thumb
For every 5 feet of ducting, there will be an addition of 5% needed in the fan's CFM. And for every ducting equivalent to 90 degrees of angle, there will be an addition of 20% to the CFM.

If you’ve a 200CFM initial fan size, then-

Fan Size considering ducting(15’)= (200 CFM + (200×15%))= 230 CFM size needed.

Fan Size considering bends(3)= (200 CFM + (200×60%))= 320 CFM size needed.