False nitrate test

[jasonrusso]

For years I have been battling nitrates in my fowler tank. It is for the most part a predator tank. I have some messy fish, the porcupine puffer is the worst. The eel isn't much better.

For the last couple of years, I've been running biopellets and dosing No4Pox. All this really seems to do is make a film on my glass and clog the filter socks.

Now, here is the issue. If I use the Red Sea stand alone test kit, the nitrates seem low. This is the kit with the 3 liquid droppers. This is the vial on the right.

The other test is with the Red Sea kit. It has 1 liquid dropper and 2 powder reagents. This test comes back as unmeasurable. It immediately turns bright purple.

If I had to guess, I would trust the vial on the right. The tank has very little algae. I would think if my nitrates were 100+, I would be battling algae outbreaks.

Is there anything that can cause a false nitrate test? I don't dose anything other than the po4nox which I would like to stop and just run biopellets. I also tried a diy algae reactor. The chaeto quickly died which also tells me my nutrients can't be that high.

On the Nano reef I just started, the powder nitrate test does come back as zero or close to it, so it does work.

 

[jasonrusso]

I should add, I do run a 25w Vectron 600 UV sterilizer. Does that affect the nitrate readings?

 

[GoVols]

Just an fyi:

I gave up on the Red Sea Pro mag kit along time ago. It would give myself false high mag readings when my mag was really 100ppm lower than what that kit read.

On that note:
Can you buy the Salifert nitrate kit to crosscheck the Red Sea?

 

[jasonrusso]

Just an fyi:

I gave up on the Red Sea Pro mag kit along time ago. It would give myself false high mag readings when my mag was really 100ppm lower than what that kit read.

On that note:
Can you buy the Salifert nitrate kit to crosscheck the Red Sea?

I can buy whatever test kit I need. Which one will I be cross checking? The one that says it's high or the one that says it is low?

Can a Uv affect nitrate readings? After a fallow period, my Kh was about 18. I haven't checked it recently, but can that affect a nitrate test?

 

[GoVols]

I can buy whatever test kit I need. Which one will I be cross checking? The one that says it's high or the one that says it is low?

Can a Uv affect nitrate readings? After a fallow period, my Kh was about 18. I haven't checked it recently, but can that affect a nitrate test?

Are you preforming the Red Sea test kits to their instructions?

UV might effect nitrates (Bacteria) but I don't run UV

 

[jasonrusso]

Are you preforming the Red Sea test kits to their instructions?

UV might effect nitrates (Bacteria) but I don't run UV

I knew someone was going to ask that, haha. Let's assume that I can read a card, put in x amount of drops or 1 level scoop of whatever. Shake for 10 seconds.

UV isn't going to affect the bacteria population unless you added it from a bottle and it hasn't settled in yet.

UV does increase redox. At the end of the day, it really does not matter with a fowler. I actually tried to increase nitrates and lighting intensity to grow algae for my foxface, angel, and tang. It won't really grow. That's why I think that the low reading is correct.

 

[GoVols]

I knew someone was going to ask that, haha. Let's assume that I can read a card, put in x amount of drops or 1 level scoop of whatever. Shake for 10 seconds.

UV isn't going to affect the bacteria population unless you added it from a bottle and it hasn't settled in yet.

UV does increase redox. At the end of the day, it really does not matter with a fowler. I actually tried to increase nitrates and lighting intensity to grow algae for my foxface, angel, and tang. It won't really grow. That's why I think that the low reading is correct.

Don't know about the UV but (lol) it seems like you do

Follow the instructions of the Red Sea kit to a tee and assume nothing, then crosscheck it to the Salifert nitrate kit.

That's the best advise that I have.

 

[jasonrusso]

Don't know about the UV but (lol) it seems like you do

Follow the instructions of the Red Sea kit to a tee and assume nothing, then crosscheck it to the Salifert nitrate kit.

That's the best advise that I have.

I'll have to check out the other test.

Something else I forgot to mention, I also did the test (powder test) with 4ml of rodi and 1ml of tank water (5 to 1 test) and it still turned dark pink. This would be a reading of 300+, snails and microfauna would instantly die and they don't.

 

[USMC 4 LIFE]

Are you adding 16 ml of tank water? Your vile seems way to low for the nitrate Test.

 

[Steved350]

There should have been a total of 16 ml of water in the bottle. For the high range the dilution 1 ml of tank water and 15 ml of RO/DI water.

 

[jasonrusso]

As I said before guys, let's assume that I know how to read. 5ml.

 

[USMC 4 LIFE]

You’re suppose to add 16 ml of tank water or 1 ml of tank water mixed with 15 ml of RODI water.

I’m not sure why the test card is saying 5ml unless it’s an old test set.

 

[jasonrusso]

You’re suppose to add 16 ml of tank water or 1 ml of tank water mixed with 15 ml of RODI water.

I’m not sure why the test card is saying 5ml unless it’s an old test set.

I think you are talking about the algae control test kit. That one only does NO3 and PO4.

This is the kit from last year.

 

[TMB]

I don't think anyone is suggesting that you can't read. I think most are used to the low range kit (Nitrate Pro) that does take 16ml of water for the test.

Do you have someone local that has another brand or style of test kit that could cross check your results?
Another option would be to do an ATI ICP test, my understanding is that they do a nitrate test during their process.

TMB

 

[Sagecritter4life]

The cards are different for pro red Sea no3 kit and standard no3 kit. The standard kit is 5ml tank water with 5 drops A.

The pro kit is low range/high range and has card with steps on front and back depending on test. Hope this helps.

 

[Sagecritter4life]

The card pictured is from the standard test not pro and is 5ml tank water and adding 5 drops tank water. It is the test I use the most then have the pro kit when want to read under 5ppm more specific than guessing color range on standard test kit

 

[Sagecritter4life]

Edit - 5 ml tank water and 5 drops A

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I do not know if anything in reef husbandry that leads to false low nitrate readings.

With many kits, a little nitrite can read as a lot of nitrate. As much as 100:1 or more (1 ppm nitrite reads as 100 ppm nitrate is some kits).

But I would not expect that to be an issue in an established tank.