Might contact Premium Guard and ask what the efficiency of their heavy duty filters are. Maybe they have the threads your looking for.
https://www.pgfilters.com/products/filters/heavy-duty/
"Superior multi-pass efficiency and removal of particles 4 microns and larger without sacrificing capacity."
https://www.pgfilters.com/products/filters/heavy-duty/
"Superior multi-pass efficiency and removal of particles 4 microns and larger without sacrificing capacity."
