There is literally 10K samples of like materials in the catalog from the manufacturer. Thread size, shade, texture as well as the thickness of material and open vs closed space is really crucial to this. We even have to do an internal process involving heat and blown air on some of the shipments as they compress them too much to be as effective as we require.
Trust me, we tried common batting as they're much easier to procure. They are far less ineffective.
We're the worlds leading (and largest) supplier of marine phytoplankton concentrates and live marine zooplankton. Hatcheries are most our business, not hobbyists. This is what we do. We want our customers successful, thus we supply the tools we feel are the most effective. Given our research in the rotifer field, and the global demand for them from us, this isn't contested by aquatic professionals.