Please help with high Nitrate level; which test kit should I relying on?

[Steven Nguyen]

Hi everyone,

I need some guidance on my water parameters and which test kit I should rely on. I have a 150-gallon tank with a mixed reef — mainly soft corals and a decent fish load.

I recently tested my nitrates and got two very different results:

• 80 ppm using the API Saltwater Master Test Kit
• 20 ppm using the API Reef Master Test Kit
• Which of these should I trust more for recording and managing nitrate levels? Should I be concerned about either reading?

Here are the rest of my parameters:

• Magnesium: 1380 ppm
• Calcium: 23 drops, 460 ppm?
• Alkalinity: 192 (assuming this is ppm, which converts to about 10.7 dKH)
• pH: 8
• Nitrite: 0
• Ammonia: 0

The tank looks ok overall, but I want to make sure I’m not missing something. Do these numbers look okay for a tank like mine? Should I consider a water change or try to lower the nitrate further?
Thanks in advance!

 

[shanepike]

I would get a Salifert, Nyos, or Sera kit and test the nitrate again. API is known to not be very accurate. (Though I would be surprised at readings that different.) Or just take some water to your LFS and have them test it.

What's your phosphate?

 

[Steve Burton]

I've used Salifert for years now for Nitrate, I only use API for ammonia when cycling a tank.

 

[jmcdona6]

I used to use the others mentioned above but switched to the Hanna Checker - Nitrate HR a while back. Testing is simple and you no longer have to question whether you are color blind or not reading between shades. You can usually find them used second hand for a decent price. Even full price I'd say its worth it if you plan on staying in the hobby.

Accuracy? Debatable as with all consumer grade test kits. But it seems to track pretty well. I certainly trust its directional reading much more than my own eyes when it comes to deciphering shades even on the best manual test kits. On the high range kits the difference in even lighting in the room can be 20 ppm.

Marine Nitrate High Range Checker HC

The HI782 Marine Nitrate High Range Colorimeter is designed to quickly and accurately determine high levels of nitrate for saltwater aquariums and marine applications.

hannainst.com

 

[gill]

Het a Hanna checker for nitrate and phosphate. I wouldn’t waste time with anything else. Easy and reliable and consistent.

 

[Steven Nguyen]

I would get a Salifert, Nyos, or Sera kit and test the nitrate again. API is known to not be very accurate. (Though I would be surprised at readings that different.) Or just take some water to your LFS and have them test it.

What's your phosphate?

It’s either 0.25 or 0.50; I couldn't tell which one it is because the colors are too similar.

 

[Steven Nguyen]

I used to use the others mentioned above but switched to the Hanna Checker - Nitrate HR a while back. Testing is simple and you no longer have to question whether you are color blind or not reading between shades. You can usually find them used second hand for a decent price. Even full price I'd say its worth it if you plan on staying in the hobby.

Accuracy? Debatable as with all consumer grade test kits. But it seems to track pretty well. I certainly trust its directional reading much more than my own eyes when it comes to deciphering shades even on the best manual test kits. On the high range kits the difference in even lighting in the room can be 20 ppm.

Marine Nitrate High Range Checker HC

The HI782 Marine Nitrate High Range Colorimeter is designed to quickly and accurately determine high levels of nitrate for saltwater aquariums and marine applications.

hannainst.com

Thank you!