Agree with Tokkay

Seems orange urates are often related to dehydration.
I was curious by the description of it being "gritty" though, as initial thoughts were that it could be passing bladder stones, so looked into it some more (be aware I'm not claiming to be a vet/experienced on this subject, just sharing related information!). If it is just a one-time thing then still a good chance it's as Tokkay explained.
Otherwise, if it's happening frequently - I would be more concerned it could mean something else. In general for reptiles, it's thought that orange/yellow urates *could* also mean; or be caused by:
- natural 'dye' from break down of food
- dehydration (as mentioned)
- uric acid bladder stones (thought to also be related to dehydration)
- too much calcium in diet (debatable, but it's thought in other reptiles this can also explain 'gritty' urates, since calcium is excreted)
- breeding cycle changes
- renal failure (from kidneys; though often times you'll find hard areas on the body; due to calcification)
- some parasites / endocrine diseases
Hopefully just a one time thing/dehydration and nothing to be concerned about

- Hons. Degree Animal Management -4 years volunteer in a Zoo -10 years volunteer in animal shelters -Enclosure enthusiast