The sub will not bother the angels much in any case as they rarely come down that far. Their colors may show somewhat better with some but that depends on how you might like it, more than the fish! I like pool filter sand as itt does all I want, is heavy enough to not get kicked up very much with filters, powerheads, and such. It is one which will not change water much in any way, so I find that easier to deal with. If it feels too bright, I mix other darker colors to get the tone I like better.