Salifert Nitrate (NO3) Test Kit

The Salifert Nitrate (NO3) Test Kit is a liquid kit for precise nitrate measurement. It is a dual range kit for reef aquariums and fish-only aquariums, and Salifert says it detects nitrate as low as 0.2 ppm (model SI021).

Why low-range nitrate matters in reefs

In fish-only tanks, moderate nitrate is tolerated well. In reef tanks, many corals do best at low but not zero nitrate. Hobby strips and basic kits often cannot tell the difference between 0, 1 and 5 ppm. A low-range test lets you see those small changes.

Dual range

The kit can read at a low, sensitive range for reef work and a wider range for fish-only systems, where nitrate can climb higher between water changes.

Testing routine

• Test weekly at the same time of day.
• Test more often if you change feeding, add fish or adjust nutrient export.
• Log results so you can see trends, not just single readings.

What to do with the number

If nitrate climbs, increase water changes, reduce feeding or boost export with a refugium of chaeto or a protein skimmer. If it bottoms out at zero and corals look pale, some reefers reduce export or feed more. Change one thing at a time.

Accuracy tips

Follow the drop counts exactly and use the same light for reading each time. Rinse the vial with clean water afterward. Store reagents cool and capped.

Freshwater version

Salifert also makes a freshwater nitrate test kit for planted and community tanks.

Pairing

Many reefers also run the Salifert alkalinity kit, since nitrate and alkalinity together explain much of what corals do.

Test before and after water changes for a few weeks to learn how much each change removes. That tells you whether your export is keeping pace with your feeding, and helps you plan changes rather than guess.