Is there any good way to grade/sift sand? I've been using generic (not '#20') Fairmount-Santrol AquaQuartz in my tanks and while it looks good, I don't think it's quite fine enough. Or, at least there seems to be a high percentage of particles that aren't fine enough. The size ranges from 0.5-2.5mm (80-85%) and the rest is 3-5mm, which seems huge for some species. Is there a way to tell if it's too large, and if so should I try and sift it or just replace it with something that has a more uniform size?