API and Salifert Nitrate tests are coming back wildly different

[FunWithFishes]

Afternoon everyone,

So my wife and I are having our baby boy tomorrow so I have been working to get the tank in pristine condition to help with some neglect that may come over the next few weeks. One of the things I have been working on is getting my Nitrates under control as a test last Saturday using the API test kit showed them to be above 160ppm.
After being devastated by that result I did the following things:

1. Tested gain using a different API test kit, still got 160ppm Nitrate.
2. Tested against freshly made saltwater, got 0ppm Nitrate. (I did this to make sure the test wasn't always reading that high.)
3. Mixed 1ml of tank water with 4ml of freshly made saltwater and tested, and it came back as 80ppm.

So I got to work on some water changes, two 30% water changes over 3 days and began dosing Nopox to help mitigate the issue. I also ordered a salifert test kit for some confirmation as I hadn't used the API test kits in awhile (though it says they don't expire until 2021).

The salifert test came in today and I ran some more tests.

1. Salifert on my tank water came back at 50ppm (Ran the test twice to verify)
2. Salifert on freshly made saltwater came back at 0ppm
3. API on my tank still came back at 160ppm

As you can see, I got some wildly different results. I know 50ppm is still way to high, but seems more manageable than 160+ppm. I know I have seen some people say that the API tests are unreliable, but usually that's in regards to the ammonia test, while the Nitrate tests are supposed to be okay.

Some tank stats:

• 150g, sand bottom tank.
• Stocked with 2 Ocellaris Clownfish, 1 Melanurus Wrasse, 1 Starry Blenny, 1 Falco Hawkfish, and 1 Foxface
• About a cube of mysis or enriched brine shrimp a day, not much of which makes it past the wrasse and blenny.
• I do have a sump with a protein skimmer and filter socks.

The fish all seem fine and have been acting normal. I have some corals like a frogspawn, some mushrooms, a gorgonia, and a duncan, all of which seem okay. I would have expected fish to die off with those high of nitrates, or at least started to act differently.

Long story short, I just wanted to know if anyone has had any similar experience. Or if anyone has any other ideas or steps I could perform to verify one of the results.

TLDR: Salifert and API nitrate tests are giving very different results. Anyone have any ideas or thoughts on who to trust.

 

[Super Fly]

I'd bring water sample to lfs & ask them to test for NO3.... API kit may have gone bad.

 

[Spare time]

Just out of curiosity, do you have peppermint and or cleaner shrimps? If you do and they are ok, I would maybe take that as a sign that the salifert is correct.

 

[FunWithFishes]

Sadly no shrimp. I have a scarlet and blue hermit crab that are both okay. I also have a strawberry crab that I saw for the first time in months last night that was moving around and seemed well.

 

[Porpoise Hork]

What kind of lighting are you doing the test in? The pink color will appear much lighter or darker depending on the color temp your room lights are. I have noticed a significant difference in the test results for Salifert when viewing under a 3K vs a 5K light. If possible use 5-6K (daylight) when doing the test to get the most accurate comparison.

Also with the Salifert kit there are two viewing angles for the nitrate test. If you are expecting a low reading, then view from the side. If the expected result is in the medium to high range then view top down. Viewing from the wrong angle or incorrect light color can greatly impact the reading you are getting.

 

[FunWithFishes]

I viewed the Salifert test from the top, since I was expecting a high reading. The test instructions say to use the side view if 10ppm or less. As for light. I used our overhead island light which is a daylight bulb, and also took it outside to view it (live in Florida and was decently sunny).

 

[Porpoise Hork]

Hmm.. Deffinitely viewing the test correctly. I quit using API test kits for all but PH as I ran into issues with reliable tests even back to back from the bulk of the kits. I have never had issues from Salifert for consistency. High nitrates can be an issue, especially if the phosphates are high as well, and that typically leads to algae blooms. Having high nitrates is no where near as toxic as nitrites so in most cases the issue will sort itself out with water changes or nutrient export by removing excess macro algae. For nitrate to be an issue it would have to be crazy high, higher than the salifert will report.

You can dose with Seachem Prime to bind to the nitrate to reduce any possible toxicity and then do some minor carbon dosing, or dose Seacham Stability or similar bacteria cultures like Fritzzyme 460 or Monster 460. These will break down the organics in the tank that are causing the nitrate spike and over a few weeks it will come down. If you decide to do carbon dosing, just be very careful as it can quickly deplete the nutrient levels in the tank and can lead to a dinoflagellate outbreak. I have dealt with this twice while dosing NoPox. Another option is to increase the photo period on your refugium or algae reactor if you have either going. The macro algae will absorb the nitrates and then can be removed when you pull out the overgrowth. Just be sure to keep an eye on the phosphates, as you don't want that to bottom out.

 

[Nick30G]

My favorite nitrate test kit is the NYOS test kit. I also have a API test kit that reads near the same as the NYOS

 

[FunWithFishes]

I just got my refugium going so I will try upping the photo period on that. That would be my preferred method of dealing with nutrient export and hoping that the chaeto will help bring the nitrates back down.

I did test for ammonia and nitrite and both came back 0, so at least I know my live rock is doing its job in that regard.

Thanks for all the advice.

 

[Porpoise Hork]

Growing and removing excess chaeto will help, but water changes, skimming and increased bacterial diversity will do a lot for you as well. Also keep in mind that just because you have higher nitrates doesn't mean it's a bad thing. Softies and LPS corals do amazingly well in a "dirty" tank and there are plenty out there with high nitrates and run full mixed to SPS dominant tanks and have no issues. The key to it is stability. In my tank it's a full mixed tank and the nitrates usually sits around 10-20, and the phosphates around .08 to .10 and no issues with anything. For example, I have a sunset mili that was a drab tan when I got it 2 months ago. Since putting it in my higher nutrient tank, it has completely changed it's color and is a beautiful neon green and growing like crazy.

So when you bring the nitrates down, just do it slow and steady. A sudden rapid drop can stress things out and possibly cause issues as well.

Just a thought.. When you are using the API kit, are you shaking test bottle 2? Years ago the owner of a LFS who used to be a chemical engineer told me to not shake the reagent 2 as it caused issues with the test accuracy despite what API's instructions stated. To prove this he broke out 4 test kits, API, NYOS, Salifert, and a brand I don't remember and tested my water. He followed the directions on each to the letter an the API came out much higher than the rest. He then did the test again with another API test kit that had not been shaken up and it came out nearly identical to the rest.

 

[FunWithFishes]

Growing and removing excess chaeto will help, but water changes, skimming and increased bacterial diversity will do a lot for you as well. Also keep in mind that just because you have higher nitrates doesn't mean it's a bad thing. Softies and LPS corals do amazingly well in a "dirty" tank and there are plenty out there with high nitrates and run full mixed to SPS dominant tanks and have no issues. The key to it is stability. In my tank it's a full mixed tank and the nitrates usually sits around 10-20, and the phosphates around .08 to .10 and no issues with anything. For example, I have a sunset mili that was a drab tan when I got it 2 months ago. Since putting it in my higher nutrient tank, it has completely changed it's color and is a beautiful neon green and growing like crazy.

So when you bring the nitrates down, just do it slow and steady. A sudden rapid drop can stress things out and possibly cause issues as well.

Just a thought.. When you are using the API kit, are you shaking test bottle 2? Years ago the owner of a LFS who used to be a chemical engineer told me to not shake the reagent 2 as it caused issues with the test accuracy despite what API's instructions stated. To prove this he broke out 4 test kits, API, NYOS, Salifert, and a brand I don't remember and tested my water. He followed the directions on each to the letter an the API came out much higher than the rest. He then did the test again with another API test kit that had not been shaken up and it came out nearly identical to the rest.

Interesting. I do plan on running a mixed reed, and zoas usually take off like wildfire so I planned on having "dirtier" water. But I figured around your range of 10-20 nitrates.

I do shake reagent 2 for 30 seconds (since that's what the instructions say). I can try it without shaking reagent 2. Should I still shake the vial once both reagents are in (for 1 minute)?

 

[Porpoise Hork]

Yes, you still want to shake the test tube after adding the reagent so it will combine. Give that a try and see if it returns a number more in line with the Salifert kit.

 

[siggy]

Congratz to the new addition, 2 water changes and get a Hanna ;Nurse Hope All is well Mr & Mrs Crabs and family

 

[Dr. Dendrostein]

Afternoon everyone,

So my wife and I are having our baby boy tomorrow so I have been working to get the tank in pristine condition to help with some neglect that may come over the next few weeks. One of the things I have been working on is getting my Nitrates under control as a test last Saturday using the API test kit showed them to be above 160ppm.
After being devastated by that result I did the following things:

1. Tested gain using a different API test kit, still got 160ppm Nitrate.
2. Tested against freshly made saltwater, got 0ppm Nitrate. (I did this to make sure the test wasn't always reading that high.)
3. Mixed 1ml of tank water with 4ml of freshly made saltwater and tested, and it came back as 80ppm.

So I got to work on some water changes, two 30% water changes over 3 days and began dosing Nopox to help mitigate the issue. I also ordered a salifert test kit for some confirmation as I hadn't used the API test kits in awhile (though it says they don't expire until 2021).

The salifert test came in today and I ran some more tests.

1. Salifert on my tank water came back at 50ppm (Ran the test twice to verify)
2. Salifert on freshly made saltwater came back at 0ppm
3. API on my tank still came back at 160ppm

As you can see, I got some wildly different results. I know 50ppm is still way to high, but seems more manageable than 160+ppm. I know I have seen some people say that the API tests are unreliable, but usually that's in regards to the ammonia test, while the Nitrate tests are supposed to be okay.

Some tank stats:

• 150g, sand bottom tank.
• Stocked with 2 Ocellaris Clownfish, 1 Melanurus Wrasse, 1 Starry Blenny, 1 Falco Hawkfish, and 1 Foxface
• About a cube of mysis or enriched brine shrimp a day, not much of which makes it past the wrasse and blenny.
• I do have a sump with a protein skimmer and filter socks.

The fish all seem fine and have been acting normal. I have some corals like a frogspawn, some mushrooms, a gorgonia, and a duncan, all of which seem okay. I would have expected fish to die off with those high of nitrates, or at least started to act differently.

Long story short, I just wanted to know if anyone has had any similar experience. Or if anyone has any other ideas or steps I could perform to verify one of the results.

TLDR: Salifert and API nitrate tests are giving very different results. Anyone have any ideas or thoughts on who to trust.

Time to pull out the sulfur denitrator, 10 or less days, will be downto what ever number you like