Join Date: Jan 2013
Location: Chesapeake Virginia, US
If this is in your aquarium, then like with total ammonia, Safe will not stop nitrite from showing up in your testing.
Per the product page: To detoxify nitrite/nitrate in an emergency situation use up to 5 g (1 tsp.*) to each 400 L (100 gallons*). Use fish to gauge toxicity reduction as test kits will still show presence of nitrite/nitrate even when detoxified. May be added to aquarium directly, but is better if added to new water first. If adding directly to aquarium, base dose on aquarium volume. If temperature is > 30 C (86 F) cut dosing in half.