i have a crapload of .20 um filters sterile nylon membrane and these work great for homebrews, solvent capable will sell cheap PM me.
they are great, ask flex he uses them too.
what are ya filtering? the membrane type is important, and the capacity, and pressure capable, smaller filters in UM are less likely to keep some hormone in the solution, the smaller you go the more filters u use and more hormone is decreased and trapped in the filter