Some sands are considered inert, some are not. Although sand has a low cation exchange (CEC)capacity it makes a great substrate bc of its small particle size. Essentially you would need to add nutrients to a tank in either the form of liquid fertilization or root tabs every so often or layer an aquarium bed with more nutrients, for example laterite clay with a higher CEC or miricle grow organic potting soil MGOPS. Then top with a layer of sand. Most people prefer to do all of the above. What works for everyone is different find what works for you and stick with it. Although for low light sand with root tabs should work just fine. Be careful your sand doesn't get to compact though bc then you could have areas of anaerobic build up.