Fast Nitrate Reduction in a Fish Tank

Old tank syndrome, or high nitrate accumulation, can be a common problem among experienced aquarium enthusiasts who neglect regular maintenance and water changes. Nitrate is the final product of the breakdown of ammonia to nitrite and then to nitrate by bacteria. Nitrate levels in the aquarium water can increase if they are not absorbed by plants or removed by water changes.

In freshwater, nitrate is generally not harmful even at high levels (over 200 mg/L). However, in saltwater aquariums, high nitrate levels (above 20 mg/L) can pose a risk to marine invertebrates. Some marine aquarium enthusiasts may be hesitant to perform regular water changes to reduce nitrate levels, as they will need to add more salt to the aquarium afterward. Instead, they may only add freshwater to the tank to replace evaporated water, which does not remove nitrate and can cause problems in the aquarium.

Fortunately, there is a quick and harmless method to reduce nitrate levels in the aquarium. This method involves an instant water change that reduces nitrate levels to zero without causing harm to the aquarium’s inhabitants. In fact, after this process, you may observe that the fish become more active, have a better appetite, and display brighter colors within a few days.

Important Considerations

It’s important to consider the pH changes that can occur when performing a water change, especially a massive one. The pH in the tank will likely increase, so it’s best to gradually adjust the pH of the tank water to the desired level before beginning the water change. You can increase the pH using baking soda or decrease it using various aquarium products designed to lower pH levels. This will help prevent “pH shock,” which can be fatal for sensitive tank inhabitants.

To test the effectiveness of this method, an experiment was conducted in which the nitrate level in the tank was allowed to rise to a dangerously high level, exceeding the scale. The experiment was successful, and the testers were able to observe the formation of different types of algae.

The established aquarium inhabitants, which included a 15-inch snowflake eel, various hermit crabs and snails, several crabs, two colonies of zoanthids, some non-living corals, and live rock, all survived the water change procedure. In fact, a newly mated pair of coral-banded shrimp were added to the tank the day after the water change, and there were no problems at all.

Quick Nitrate Reduction Technique

Performing a series of partial water changes can be an inefficient way to reduce nitrate levels quickly and effectively. While it will reduce nitrate levels, it is not the most efficient method if the goal is to reduce levels to near zero as quickly as possible with minimal water changes.

Instead, a more effective method is to reduce the water level in the tank to 20 percent of normal and then refill it to 40 percent. This will already reduce nitrate levels by half. Then, reduce the water level again to 20 percent and refill it to 40 percent once more. By doing this, the nitrate levels will decrease to 10 percent of the original level. Repeat this process once more, and the nitrate levels will decrease to just 5 percent of what they originally were.

Using this method, a starting nitrate level of 100 parts per million can be reduced to just 5 ppm, which is considered acceptable even for corals. This method is much more efficient and effective than performing multiple partial water changes.

Why It Is Safe

While some aquarium owners may worry that rapidly reducing nitrate levels could harm their tank critters, the reality is that allowing nitrate levels to continue to rise is even more dangerous. It’s similar to being in a closed garage with a car engine running and carbon monoxide levels rising. In such a situation, it’s crucial to reduce the toxin levels quickly, even if it means rapid changes.

Of course, the best way to avoid the need for an urgent nitrate reduction is to maintain a regular schedule of tank maintenance and water changes. However, if you find yourself in a situation where you need to quickly reduce nitrate levels, this water change method is worth considering.

It’s important to note that you can use this method conservatively if you’re concerned about the well-being of your tank inhabitants. Rather than performing the water change process all at once, you can spread it out over time, waiting a few days between each change until the nitrate levels have been successfully reduced.