Well, yes and no. Sure, scrubbers can and do trap particles and to some extent can act as export that way and be supported by it. That is one of the adaptations of filamentous algae that gives them an edge. Filter socks wouldn't be able to increase local pH and system pH, though, and wouldn't be able to induce PO4 precipitation (at least under certain conditions). I suppose a more accurate way to compare it would be somewhat similar to having a filter sock laced with LaCl3 (except potentially more soluble) when conditions are favorable.