Carbon filter and fan size

A 4" fan should be good but check the size of your holes for ducting. You'll want to exhaust around 200/300cfm,most fans will tell you what they do and there size and dimensions, you can get some included with carbon filters but they may be a bit flimsy try to find seperate one that looks a bit sturdier👍🌱

I am in a similar space and have a rhino pro 4" and Rhino single speed fan never smell anything, unless i open door up

I use currently 60x60x170 and the RVK100MM x 300MM set up. The fan and Carbon filter size works wonders,(The brand I use is PrimaKlima) great environment for my girls.

Where could I buy a decent 4inch fan and filter from?

Get a 4 inch 200-300 cfm fan and filter kit should be perfect for your tent size!! Happy Growing! 👊

A standard 4" fan and filter combo should handle that easily. I chose a combo setup by IOBionics that included fan, filter, speed controller, two clamps, two rope ratches, ducting, and a hydrometer - all of which you may need as well (the tent usually includes belts that'll work but the rope ratchets can be used for your grow light). You don't need more than 4" and the only "benefit" will be more energy consumed and noise. Whatever you buy, I highly recommend spending the extra on a fan speed controller as they are all loud on full, which is the only setting without one; with a fan controller, you may never need to turn it beyond half way where its still pretty quiet (I veg with mine on low and turn it to medium for flower when I need lower temps and humidity in the tent).