I am thinking of changing my sand filter to a Nautilus FNS 48 DE filter. My water seems fine however I see particles floating at nite with light on. I also see dust when I brush and was just wondering if a DE filter would remove this. I can get this filter which is used for very little money however I would have to replace the grids. The filter is an older model and is black, not sure how old it is. Is this overkill for my pool. All thoughts are welcomed.