A wish from the Sand

In the kingdom of the elements, it is believed that there are water spirits who grant wishes in certain circumstances.  It is believed if you gather up a handful of sand and take it home it is good luck.  It is believed, if you go through this handful the sand and find the ten largest grains, these are wishing grains.  If you have a wish take one of the ten wishing grains out into a field of grass, say your wish, and toss the wishing grain over your shoulder.  If you can turn around and find the wishing grain in the tall grass, your wish will come true.
If someone from the kingdom of the elements takes a trip to see the seaside, they will almost always bring a handful of sand back.  Some believe in wishing grains, others believe in the luck of having sand in their house.  Some just do it out of tradition's sake.  The story for why this is, goes as follows:
Long ago water spirits were land-dwelling like us, but when they first saw the ocean, they swam so long their they couldn't be without the sand beneath their feet.  Over the centuries only the lucky have survived out there on the terrible ocean.  they say ocean spirits can come onto the beaches at night and walk along the sand.  They say they love land and miss it but can only go where there is sand.  And so, if you bring a handful of sand into your home, a sand spirit can visit your home and they trade a little of their luck for your kindness for inviting them.
The spirits can be seen at night walking on the edge of the water.  light silhouettes who drift around the beaches.  These spirits will scamper back into the ocean if someone approaches.  The truth is, they are simply ocean spirits, they feed off salty air.  They cannot leave the ocean or beaches because they need the salty air.  They will not visit your house if you have sand in it, and they are not lucky.  In fact, they aren't even very intelligent creatures.  They are slow-moving shadowy figures who feed off water and salt and glow in the night.  They can't be in the sunlight, that is why they walk the beaches only at night.  No, if you bring sand to your house, they will not visit.  Not sure they even know what sand is.