Using 6 to 4 reducer to match up 6" Can Fan to a 4" carbon filter

I have a 6 inch Can Fan S600 which is approx. 275 CFM (overall a pretty decent fan imo) that I want to make work with a 4 inch filter. Reason being is that I have recently downsized to a smaller 4'x2'x5' tent and need to use a smaller sized filter due to space constraints. Is this worth doing? ie: Will this work efficiently enough to scrub the air or should I just try to find a random, smaller sized, 6" filter to go with the 6 inch fan? Any help regarding using a reducer would be appreciated. Thanks

It will probably pull more air than the filter is able to scrub resulting in smell. You can use controler to lower down speed of your fan or just downsize it.

On top of that it will reduce your fans efficiency, so if you needed the 6" on full to stay in range it's an issue, if you only need to run at 50% then shouldn't be too much of a problem.

Not an ideal situation though. I upsize all filters to ensure better scrubbing and longer lasting filter.

Another option would be an inline filter instead of reducing size to fit in tent.