You CAN use Builders or All Purpose Sand it is much courser than Play Sand and works just as well as Poultry Grit.
There are two types of Grit Insoluble Grit (stone and or crushed stone) and Soluble Grit Oyster, Cockle shells and or limestone)
Grit that is too small will simply pass straight through the bird and will not help the bird at all so it is worth checking that the grit you are buying is for the correct age of bird. Grit is usually classed as chick, grower, layer and turkey. It is better to feed a grit that is slightly too big than too small. Soluble Grit will do little help is digestion/ grinding there food.
Birds that free range will usually pick up enough grit from the ground however there is no harm in providing additional grit for birds to take if they need it.
Thanks, that was very helpful. I think the sand I have in there now is play sand - I will look for other sand or head to the ranch store for grit