Nitrites, while beneficial in small amounts to a healthy aquarium environment, can be toxic if the levels become too high. For this reason, it is important to keep an eye on nitrite levels and take action when necessary. The good news is that nitrite levels usually drop relatively quickly once steps are taken to reduce them. Depending on how much water has been changed and what other treatments have been applied, nitrite levels can decrease by 50% within 48 hours of treatment. In addition to performing frequent partial water changes (25%-30% every two weeks) using dechlorinated tap or purified water, adding live plants to your aquarium will help reduce nitrites naturally as they absorb nitrogen compounds from the water column and convert them into harmless substances like oxygen and carbon dioxide. Other measures such as increasing aeration with air stones or power heads can also help speed up the process of reducing nitrates in your tank. Ultimately though, all tanks differ so there’s no one-size fits all answer for how long it will take for your particular tank’s nitrite level to go down; however many hobbyists report that their tanks show positive results within a few days after taking corrective action!