So glad you wrote me about this issue since we are both in Florida. My biggest problem is his house is next to my house which sadly is a stucco covered frame home so i cannot put wood type mulch next to it since it had termites from the previous owner.He or she is a decent size.
I'd sift out some cypress mulch to cover up that sand. I say sift, because I've found things like metal wire and plastic in my cypress mulch. Pure Cypress is our most common type here in south Florida and I've been using it with no issues for decades.
The best part is that as the mulch breaks down. You ad more and it becomes a nice humid layer of the best plant soil ever. And the plants love it.
Sand needs to be avoided in outdoors pens when you can. I know that's difficult if not impossible. But covering it is the option that I use.
Tortoises can't digest sand and neighborhood cats like to poop in it.
Since then the issue has been corrected but the pest guy said get all of your mulch from your flower beds away from your house so the termites won't choose to by pass the traps. I have planted in the ground...which i actually dug up a few to put buddys house near my office window so i can see when he wakes up.