good question!!! it was only recently that i got the rays. until then i never had floating particles issue with my aro, bichir & severums; and regular vacuuming would clear up any light particles stuck among the substrate.
ever since the rays arrived, their pellet food & bloodworm diet leftovers have started to collect within the substrate, & the rays stirring up the substrate (round/smooth edged stone) has not been any beneficial in keeping the water clear.
so now, i have put in a Sicce power head to ensure there is a decent water current to move the leftover food towards the filter mouth. frequent vacuuming will have to continue though!!!
since i use canister filters, a sand substrate is out of the question for me. & since the tank is in the main living area in my house a sump filter drain sound would be just too irritating...