Donor,
!!!!! PLEASE Do not use that. That filter is way too dense and interferes with the free flow of air. Also the grating/mesh that holds the filter has significant obstruction and I'd guess it is at least 30% reduction from just that! Ours are not engineered to have any obstruction.
The 256 has a low duty cycle as it is at max. You will damage the machine seriously.
ANY air restriction is forbidden and will void warranty. You must keep 1 foot clearance from any obstruction additionally to provide maximum air flow.
It's better to remove the cover occasionally and blow out the inside with an an air compressor, and and air gun/wand.