Is it sand or gravel?

[GaryE]

Soooo, what is the line between sand and gravel? I see each discussed here, but are we talking about the same things?

I can buy pool filter sand, which is great for my tanks. I can also get pool filter gravel (it says so on the bag) which is exactly the same stuff.

I'm asking a dumb question, but sometimes I wonder if we're talking about the same thing. To me, none of the pool filter stuff is sand - it's fine gravel. Sand is like play or construction sand.

 

[PheonixKingZ]

Sand is fine particles, grave are large particles.

 

[GaryE]

Sand is fine particles, grave are large particles.

True, but where is the line? I know it when I see it, but the words get thrown around here a lot and at times, I suspect people I read are talking at cross purposes.

 

[DoubleDutch]

Google says this :
Sand—rock fragments or mineral particles that range in diameter from about 1/16 to 2 mm (from 0.002 to 0.08 inches). Gravel—chipped or rounded rock fragments that typically range in diameter from about 3 to 75 mm (0.125 to 3 inches).

The different between PFS and the other mentioned types is PFS is more or less the same size and mote important shaped the same (polished and rounded) which provides the characteristics (to stay open en let water through) the other sands haven't / have less.