bought this to fix fuel drain back problem

I think some of this is related to the late model evaporative tank system IE the "carbon can" some of it may be "modern fuel" that is alcohol and some might be leaky pump check valves, and some of it might be either improperly installed or modified system parts (over the many years) or things plugged allowing vent problems.

Before I went to EFI the best things I did on my car was simply abandon mechanical pumps, went to a rear electric pump, a carb insulator, and the forementioned Wix style return port filter. They do work.

This too is a band aid of sorts.