Bag/Sock Micron Size to Catch Chaeto Pieces, but not Copepods

[Kurtz]

I have a Waterbox 20 Nano running a Tunze Algae reactor. The return for my reactor feeds into the same chamber as my return pump. Loose bits of chaeto are flowing into the chamber and eventually cause my return pump to clog (even with a cover on the intake). I was thinking a simple solution would be to put a bag over the line leading out of the reactor that would be large enough to catch any chaeto, but big enough to let any copepods pass. Does anyone have a suggestion on what I could use or what micron of a bag I would need?

Thanks in advance for any advice and help.

 

[Mical]

I had a similar problem w/chaeto getting into my skimmer, I use these now & cut to fit -> https://www.bulkreefsupply.com/pf-overflow-replacement-foam-sponges-eshopps.html