I would just take that sand and spread it all over the yard. If you have depressions or holes in you yard you can fill it with the sand.
As someone stated already about a cartridge filter. I would get rid of the sand filter and put in a cartridge filter . So much easier to maintain. Sand is old technology. Time to update.
Had the cartridge filter setup for my swimming pool at my old house. It was easy to clean , loved it.