Its your tank hun!
If YOU feel you need it and wanna spent the extra money, go for it.
Me personally I'd not buy it and IF needed (which I doubt with a good water source & proper lights like I said before) IFF you still need something then buy plant fertilizer.
And here again, you can gladly spent the $ for "Aquarium sand" or go to any home store and buy Play sand (I say play sand cause "random" otherwise used sand for eg. construction could have other stuff in it you don't want, play sand if child safe so no additives).
Hope that helps ya.
I'm no expert, but play sand compact in the aquarium, which is a bad thing. look for something cslled "filter sand". It should be about the same price or a tiny fraction more, and will work better. (filter sand allows water to flow between the grains i.e. lets nutrients get to the roots.