Nitrates are the end result of the biological filtration in your aquarium system and certainly the biggest reason you find yourself tangled in hoses and wrestling with buckets. Aqua Medic offers some relief, with a complete line of Nitrate Reductors, including 2 models designed to cover aquaria from 75 to 800 gallons. The all natural process works for both fresh and saltwater systems to reduce or eliminate nitrates. You will enjoy fewer water changes, less algae to scrub, fewer problem-algae blooms and better animal health. Just the reduced water change schedule alone will improve your system stability, lower the costs of maintenance and allow you more time to enjoy it! The Nitrate Reductors utilize a sealed chamber through which water is pumped very slowly, creating a low oxygen environment. In these anoxic conditions, naturally occurring bacteria breakdown nitrate (NO3), to use the oxygen it contains, entirely removing it from the system. The Deniballs filter media is a carbon "food" source for these bacteria and they should be replaced annually. For optimum control and a minimum of fine-tuning effort, we recommend using an Aqua Medic mV Computer to regulate the flow through-put based on the mV value within the reductor