I know it's likely too late but our big sand rinse thread shows you can make any tank immune to this condition by simply rinsing all that out before you set up the tank. If this is a nano, you can still do that
People don't pre rinse because they fear harming the bacteria in the sandbed but it's not the case for two reasons: 1. Surgeons and microbiologists only wish that rinsing in water was an antibiotic move, it's not and 2. We don't need the bac there anyway...which is how bare bottom tanks survive using what bacteria the rocks house.
If the tank is large-ish you can still prep it the right way by draining the clean water into a Rubbermaid or brute trash can, taking out rocks and animals into a holding container, then fully removing the sandbed-rinse, and reinstall it all using skip cycle techniques
It's true in time that biofilm will coat the surfaces and lessen it all but the ideal sand prep makes it a non issue permanently