Fluorite

Ah, you want it 'white' white. lol. Never mind. You might have a hard time finding that cheap.
 
I once had a really WHITE white sand but I don't know where it came from...I got it from a friend who was a mason so I think it was some sort of masonry sand. Very very fine and soft and WHITE. Maybe you could call a quarry? I dunno if you have any.

the problem with it was it didn't stay white long. It seemed to age to a very yellow/off white pretty quick. I don't know if this is a problem with all white sands, but it wasn't nearly as attractive as a sand that's just the color of say aroganite to begin with.


oh one other options I've done...I dunno if you have Fred Meyer or any other one-stop shopping equivalent, but in the houseplant section they have little bags of decorative sand that I've used. You have to wash it REALLY good but it's glowing white. you don't get more white. It comes in little bags for like $2.99 each.
 
Different pool supply places have different color sand. You could call & ask, they usually know what color they have. Be warned, white(ish) substrate shows all the detritus.
 
It took our Fluorite forever to get clean. We mixed it with Play Sand and had to wash the crap out of it too. Our tank still stayed cloudy for about 2 days and then was good to go. My plants develop roots soooo fast in Fluorite. I love it!
 
If you want a very "white" sand. I bought mine at a Menard's (google it) fifty pounds of handy-sand for 5 dollars. It is very fine and white. You will want malaysian trumpet snails to keep it from compacting, also it will never stay crisp white.
 
i dunno if it's as white as you want, but i recently bought a 50lb bag of hth pool filter sand at my local hardware store and it's the lightest stuff i've found. shows some* color, but not much imo.
 
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