Fans and carbon filter

I was wondering if I can use this setup because I’ve already got it at home. I have a 3 foot by 6 foot by 6 foot grow area. I have a 200 CFM blower fan and it’s a 4-in. I have a 6-in 440 CFM exhaust fan with a 4-in carbon filter. Can I buy a reducer on the 6-in exhaust fan to go down to my 4-in carbon filter. I’ve read many places that the filter and hoses can take up 30% of your fans CFM and that’s why I’m trying to use my 6-in exhaust fan. do I have to buy a 6-in carbon filter or can I use the 4-in when that I have

You could do it the question is should you do it? Carbon filters are designed to support a certain CFM. If your fan exceeds the design of the filter you will loose the dowel time in the carbon and reduce its ability to do its job.