In her book (Ecology Of The Planted Aquarium), Diana says that she layered the tank bottom with potting soil and covered the soil layer with small, natural gravel.

However, in her thread about New 50 Gal Setup and her article about Small Planted Tanks for Pet Shrimp, it seems that she doesn’t use any kind of gravel, just sand – pool filter sand.

From what that I know, gravel, sand and pool filter sand comes with different particle size. Pool filter sand seems like builders sand for me.

When I asked Diana about this, here is the answer,

dwalstad <…> 18 Juli 2012 07:04
Kepada: Novianto Sutardi <…>

Dear Novianto,

I used sand for the sake of the shrimp. They might be happier living with rocks than boulders!

I have used both play sand and pool filter sand. I would not worry about particle size. I think pool filter sand might be a little cleaner than builder’s sand. After all, it will be used to filter a pool. I didn’t know what’s in builder’s sand, so I never used it.

Best,
Diana