That's what we're pre rinsing for thirty pages in the sand rinse thread, to prevent these headaches from the day of setup
A bag of caribsea sand has no wiggling animals, and rinsing out silt isn't antibacterial. It's not that filter bacteria for reefs are weaker than other bacteria which require cleaners to sterilize.
We've made a killing in linkable work threads convincing people to pre rinse, that's a certain fact. If you want this cleaned before you pack with corals it's good time to catch up. Not one cloudy tank persisted in the sand rinse thread
A stick test for the sand is ideal for assessment.
Fast forward three years: it'll have detritus, heavy fish loading above it, plus silt. You could remove a third of perpetual clouding by rinsing, again it's just a distillation of work threads, there's a pronounced need for clean water in the hobby. We force tanks clean vs coax.
No new water needed
Drain off current water, catch in some huge pool/ big tanker problems
Fix sand per thread, put old water back it'll filter well now