Dust with filters on radiator fans?

[Shadowman]

Ok so its been about 4 months i installed my 360 radiator EK XE 360 with fans as intake has a 360 dust filter from DEMCiflex. Ok so today i thought i give my radiator a clean i took off the fans and there was so much dust on the radiator fins? the weird thing  is the fans front blades had hardly any dust at all but the rear side of the blades which are closest to the radiator fins had so much dust as well? i mean what is going on here? could it be the filters rubbish at keeping dust out?  I would like to point i have 420 radiator also fans are set to exhaust air out on the 420.

 

[Dschijn]

The filters are not blocking all the dust. Threre are still small dust parts that can pass through.

[Shadowman]

53 minutes ago, Dschijn said:

The filters are not blocking all the dust. Threre are still small dust parts that can pass through.

Thanks, so what can i do to keep these small parts of dust out? Also just out of curiosity could it be the pressure in my case? i have 3x 120mm fans on the 360 pulling air in however i have 3x 140mm fans pushing air out ....oh and plus there's a 120mm fan on rear as outtake as well.

[Dschijn]

You can get better filters, but they will restrict the airflow even more.