Ugh...that sucks.
IME, AEFW's are poor swimmers. They are not going to be able get out of filter socks. I'm thinking that if you have a dedicated frag tank, using a UV sterilizer with a slow enough flow through it to completely kill everything that goes through it will keep AEFW's from going from one tank to another in the same system.
Maybe get that going with flow from display to frag tank. UV from frag tank back to display. Slowly treat, cut, rinse frags one at a time until they are absolutely AEFW free, and then move them to the display. Eventually, you will have moved all contents from frag tank over to display without AEFW's. Take down and clean the frag tank, and then restart it with the UV in place and eventually, get a UV for the display to frag tank line as well, thereby ensuring both tanks are in the same system, but somewhat separate for pest/disease purposes?
I know I'm being pretty cavalier with your money and time...but it's a suggestion.
Are you thinking you got AEFW's from someone/somewhere locally, or an online vendor?