What type of sand are these? The sequal

[Barry Tetra]

so I just bought these sand from my LFS, kinda expensive 40$ (1200thb) for 10 kg
but it is the best sand I’ve ever experienced they sink to the bottom of the tank and not cloudy at all, what type of sand are these?

@seangee

 

[ember04]

That looks like pool filter sand to me but in no expert