Not sure just how fine "fine" is, was thinking pea gravel vs "medium" marble size. Most of the net pots i have seen on the net are slotted with larger openings, ....never really know what you are getting until it arrives at your door. The 5" ones obtained from my local aquarium shop are tighter mesh for holding back fines and I wish i could find some mesh 3" pots....but already ordered the slotted version....currently have been using a mix of perlite and a red "clay" chipped aggregate media for planted aquariums, not expanded, but comes from georgia not germany......seems to have been doing well except for more fines = more dust........was hoping to upgrade media and improve results. i have to come up with something my media mix prolly wont stay in those slotted cups. Maybe try out some locally available lava rock as well.