Originally Posted by mart
Mine would only be for a 5.1 tank, so 5lbs should be enough.
Plants do ok in it? My other has just gravel, and the plants are doing fine. I don't even add any fert to them.
Gravel and sand (of any sort) have essentially zero nutrients, so you'll need to add some sort of fertilizers for your plants. You might get away without it for something slow growing and low care like Anubias or Java Fern (but they don't get "planted" in the substrate anyway), but for rooted plants, swords, etc. you'll want to add root tabs (stick in a new one every 4 months, generally), and probably some sort of liquid fert like SeaChem Flourish (twice per week).
Make sure you're getting the BLACK Tahitian Moon Sand, btw (if that's what you want). It comes in a number of colors. Not super clear that the one you linked it black, at least from glancing at the photo.