Nitrate is not really the enemy sparsely; low however detectable ranges can embellish coral color

https://hotel-wiki.win/index.php/The_Impact_of_Temperature_on_Coral_Health_in_Your_Saltwater_Aquarium

Nitrate is not really the enemy moderately; low yet detectable levels can amplify coral color and expansion devoid of fueling nuisance algae blooms.