I had that concern as well, but when i remove my filter socks for cleaning I have only seen a couple of the big nasty ones in there. I;m using a mesh sock right now, which has huge holes instead of the felt ones so I'm sure the pods
are getting through that one. BUT the mesh sock kinda stinks, it has such large holes I feel not enough is getting captured.
Jury is still out on this. I only bought one mesh sock to try as I was changing the felt ones out every 3 days or so because of them getting clogged.
I still ahve a massive pod population int he main tank and a bunch in the refugium, but mostly the big ones. the little baby pods
are hiding I guess. lol