In the US I use pool filter sand, specifically this brand that I buy from Ace hardware stores. They usually have it only seasonally but would get it for you at any time. Many years, very satisfied.
Buy HTH 67120 Filter Sand for $14.99. ➤➤ Shop for Filter Sand at a Do it Best store near you. Top selection of Pool & Spa Chemicals. ✅ Hardware home center
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About beige vs white - the sand above is a light tan (not white). The whitest sands are undesirable, but bear in mind that any light color sand will quickly darken a bit once in use in the tank. I am not talking about accumulation of gunk, but instead microscopic biofilm around the individual grains, which darkens them a bit. They include beneficial bacteria, a good thing. Edges not too sharp, grain size about optimum for plants, fish and filters, and poop and debris stays on top so it is easily vacuumed during maintenance. Good luck!