Either that or find a method to keep it intact under the case.
The CM690II suffers from the exact same flaw.
I have a hybrid psu so taking 4 screws out and moving the psu to access the filter isn't so bad.
Still a PITA and a stupid flaw considering the 690II has a filter for 2x120mm fans right beside the psu cutout/filter.
The filter for the fans is outside of the case! lol!
Oh and btw when i did have the presence of mind to check the psu filter it was clogged right up.
And i don't keep my cases on the floor.