Boomer said:Nitrite in seawater
Aquarists' concerns about nitrite are usually imported from the freshwater hobby. Nitrite is far less toxic in seawater than in freshwater. Fish are typically able to survive in seawater with more than 100 ppm nitrite! Until future experiments show substantial nitrite toxicity to reef aquarium inhabitants, nitrite is not an important parameter for reef aquarists to monitor. Tracking nitrite in a new reef aquarium can nevertheless be instructive by showing the biochemical processes that are taking place. In most cases, I do not recommend that aquarists bother to measure nitrite in established aquaria.