How long have you had the sand bedding?
@Dlepage ...
Where in this world are you located?
Climate, and time of year, is almost always a factor.
Please add your general geographical location to your profile.
It's easy to do, and then it's always there!
It doesn't need to be 'deep' to work.
A couple inches of coarse wood chippings work here,
but I'm not trying to make garden soil, just keep the poops breaking down.
I do add some other dry plant matter if I have it.
Best if you have a place to store a big pile of chipped wood from tree trimmers.