Mine is about 12 to 18 inches deep I love the sand perfect for my girls but I'm in cali. If it's somewhere that's too hot or too cold it can be very problematic for sure.
I read a blog by the chicken chick and she said to used washed and strained plaster or river sand. That sand is cleaned and strained. Beach said has all kinds of stuff from seaguls and other birds. Also the river sand or
Plaster sand has small pebbles in it. So the sand is great for grit...