I second what others hava said, but if only possible, choosing sand garvel size +1mm will help. It helps water circulation in the sand. I happen to know many, including my self, who has got anaerobic areas with too fine sand like 0,1-0,5mm. However, I also know many how have pretty fine sand without problems.Too thick layer of sand might lead to problems despite the size of the gravel. I personally like sand and never do vacuum or use sticks. I always have lot of cories taking care of bottom plus a plenty of flow taking care of bottom water/nutrition/oxygen/waste circulation. I have found gravel size 1-2mm best, never problems with it. As said, plants do fine just with water column fertlization, but adding root tabs is also fine with sand. Especially aponogetons, crypts, lilies and swords enjoy it!