Is it possible my cat still has crystals?

What do you mean by pees on everything? Do you mean spray, or squat and pee? Spraying is a territorial thing that ALL felines exhibit, neutered or not! Especially if they live within a multiple cat household. Squat and peeing could be behavioral as well within a multiple cat household. Take him to the vet to rule out bladder or urinary tract infections to eliminate those possibilities first. Does he ever use the litter box? If you do have a multi cat household, rule of thumb is 1 litter box per cat plus 1.