At some point you’ve probably stared into your tank and thought to yourself… Something isn’t right here. Why are all of my fish hiding? Why does that glass have algae growing on it? What’s going on here? Chances are it’s nitrate. Nitrate is one of those slow building chemicals which can cause havoc in your aquarium without you even realizing it. Fish won’t gasp for air at the surface until much later when it has done its damage. Nitrate can’t be smelled or seen. The only protection you have against a slow, painful crash is frequent water testing.
What do those colors translate into in terms of your livestock? How does it map out? On one side are those conditions that are lethal. Killing sensitive fish in a matter of hours; on the other side, those conditions that may still be harmful but are acceptable for more robust species such as corals. Many hobbyists assume that anything less than 20 parts per million is okay. For hardy LPS coral, that’s already considered stressful. A little over a part per million above that could easily mean the difference between life and death for a coral colony or some other sensitive marine creature. But for a goldfish, no problem.
How to Keep Nitrate Levels Safe
This context is absolutely critical and is where color chart is best at helping you understand the difference between safe and hazardous ranges. Every single drop of test reagent now has context. Most testing failures come down to one specific mistake involving second bottle. Reagent two should of been shaken hard for thirty seconds. Full seconds. It’s tedious but there’s no wiggle room here. Those chemicals are all agitated up in there and they requires proper dissolving to work as intended, to react with your sample. Rushing through this part or skipping over it entirely results in a false low result, which could lead you to believe your water isn’t toxic while really it is. Use your phone to set a timer if necessary. Thirty seconds. Do it right the first time. Save yourself days of troubleshooting false negatives by not cutting corners.
Also, consider your nitrate sources and sinks. Food = waste = nitrate. Fish waste are a source of nitrate, too. The number one cause of this in most people’s houses is overfeeding. They pour on flakes like they’re going out of style and then let half of it rot on their substrate. That rotting fuels the nitrogen cycle that produces nitrate. Nitrate builds up slowly if it isn’t managed correctly.
Here, water changes are primary method of export. Consistent water changes physically dilute the nitrate concentration. However, the weekly 25% change is superior to a huge monthly purge because it keeps nitrate from ever building up to dangerous levels. Here, water changes is the primary method of export. Consistent water changes physically dilute the nitrate concentration. However, the weekly 25% change is better than a huge monthly purge because it keeps nitrate from ever building up to dangerous levels.
You also cannot take a “one size fits all” approach to this. What works for planted tanks won’t work for every system. Live plants consumes nitrates as fertilizer for new growth. Therefore, nitrates are not toxins but nutrients in planted tanks that can handle higher levels. However, if you’re keeping sensitive fish (discus) or corals (SPS), you must maintain very low levels, i.e., near zero. That’s where the chart helps highlight the threshold levels for various inhabitants, such as shrimp and SPS corals. What you keep in your tank dictates how often you should maintain it, not necessarily what’s convenient during the weekend.
It’s not so much what one reading means but rather how it compares to other readings and trends over time. Is there a noticeable increase of 10 ppm from 10 ppm to 20 ppm? That says something different than a consistent 35 ppm. By tracking your readings, you can identify slow leaks when it’s still manageable as opposed to waiting until it becomes an emergency. You’ll also know if your regular tank cleaning routine is really making a difference. If your water changes are keeping your readings steady but they’re consistently trending upwards, then you’ve got a source problem (e.g., overstocking, hidden detritus in the filter).
So what does all this mean? It boils down to one thing, observation and discipline. Feed lightly, shake well and test frequently. If you fight the cycle, it fights back with elevated nitrates. Respect the cycle and those nitrates will dissapears. Every time you look through the glass, you’ll see your starting confusion turn into confidence as your fish become active and your colors pop on crystal clear water.
