The size looks good. I wonder if it may be a bit angular, hard to tell from pic. I think it is important that the grain have a rather eroded, tumbled texture, so that it is less angular, more rounded, less abrasive. This way it is smoother on any part of the fish that comes in contact to it. If it feels rough to your touch, it's rough on the fish, especially if you have cories, rays and bottom dwellers. If you can hold some in your fist and make like you are washing your hands with it, and still feel it rather smooth to your touch (kind of like a facial abrasive compound), that is what you are looking for. The tips of the ventrals on altums and angelfish in general are in frequent contact with the sand. A sharper grain will wear off the slime of the ventrals and open attachment areas for bacteria. In cases of fright, a sharp sand can be quite harmful if the fish dodges into it for whatever reason producing severe lesions of skin and eyes.
God listens. He may not always give you everything you want, when you want it; but he always gives you what you really need, when you need it most!