I would agree as well about not using the silica (not silicate) sand. Most regular playsands are silica sand and will do ok, however, it will not buffer the water and can, not definitely, but can leach silicates into the tank after long periods of time. Aragonite is more expensive, yes, but looks and does much better for the tank. It will help keep the water buffered and is also safer for sand burrowing, munching gobies...
I used to use the silica sand and after about close to 3 years, switched to aragonite completely. The difference is highly noticeable.
As with what others have spoken on this site about CC, heed the words... Sand will be much more pleasing and natural to look at as well as keep up with. JMO