NO3 testing confession and heresy

EMeyer · 11/15/2018, 12:04 PM

OK, folks, I have to make a confession. I've stopped doing nitrate tests a long time ago. Some readers may find my reasoning obvious and wonder why I'm rehashing accepted wisdom. Other readers may find this crazy. Well, I have a crazier one for you.

I dont believe the numbers people report on forums from NO3 tests mean anything whatsoever, unless something has gone very wrong and the tank has 20+ nitrates. So I think anyone keeping a healthy reef tank who is doing NO3 tests is probably throwing away money on these tests too.

Here is the thing. In about 5 years of testing water in a series of 6 different tanks, I have never, ever, seen a nitrate level thats different from zero. Salifert tests. Rock solid zeros always, except for during cycling.

Why is that a problem? Doesnt that just mean my tanks are low nutrient? NO. I clean algae off my glass every 3-4 days. There is obviously, unarguably, NO3 in the water.

Even worse, take a look at those color charts. I've compared the kits. Can we stop fooling ourselves? The human eye isnt going to detect a difference between 0 and 5 on Salifert, or any other test I've looked at. A person can look at the chart and subjectively, based on their mood, the weather, and the lighting in the room, decide to mark down one number or another. But lets not kid ourselves. All we're really doing is saying "there is not much NO3 in my tank". We cannot tell the difference between 0 and 5, let alone 0 and 2, with these kits.

Is there a place for NO3 kits? Sure. Two places. Cycling and tanks where something is going wrong. I'd put these test kits right up there with Cu test kits: limited to very specific cases, not useful for daily or weekly testing.

In summary: in my experience NO3 tests appear to tell me nothing about the level of NO3 in my tanks. Still doubt it? I dose my tanks daily with 2 ppm nitrate (final concentration, calculated from mass and volume). And even after those doses, cant see any change in NO3.

I will be curious to hear feedback. Prove me wrong! I like testing and believe in water quality testing but I just do not see any evidence there is value to NO3 testing.

[I should add the caveat here that I have not explored Hanna NO3 tests; in principle a spectrophotometric assay has the ability to detect these low concentrations in an objective and reproducible way]

Uncle99 · 11/15/2018, 02:07 PM

I keep nitrates at 3ppm and do a water change at 5ppm.
Both too much and too little make my corals unhappy.

outssider · 11/15/2018, 04:58 PM

red sea nitrate kit shows a big difference between 0-4 but you may be right because my tank always shows ZERO and I have to clean glass every 3-4 days too !!... (-0- P04 also)

EMeyer · 11/15/2018, 09:26 PM

Red Sea kits. Interesting that some online images show a range of invisible to barely visible pinks like this
https://*******.com/y946xnhx
And others show a qualitative change from pale blue to pale pink
http://wiki.aquatribu.com/images/7/7b/NO3-Red_Sea.jpg
Thanks for the tip I will have to investigate further. I reached my conclusion based on the invisible to barely visible pink scale... which matches the other tests I'd used.

[Am I misunderstanding something? ************ and ******* are both censored? Thatd be kind of odd.

LOL, they are. OK nevermind.]

bertoni · 11/15/2018, 10:28 PM

Nitrate seems to be hard to pin down as to its effects. I don't see any reason to measure as long as the tank is doing well. I might consider measuring once every few months as a safety measure, but I didn't in the past.

Scrubber_steve · 11/18/2018, 06:48 PM

Quote:

Originally Posted by EMeyer

OK, folks, I have to make a confession. I've stopped doing nitrate tests a long time ago. Some readers may find my reasoning obvious and wonder why I'm rehashing accepted wisdom. Other readers may find this crazy. Well, I have a crazier one for you.

I dont believe the numbers people report on forums from NO3 tests mean anything whatsoever, unless something has gone very wrong and the tank has 20+ nitrates. So I think anyone keeping a healthy reef tank who is doing NO3 tests is probably throwing away money on these tests too.

Here is the thing. In about 5 years of testing water in a series of 6 different tanks, I have never, ever, seen a nitrate level thats different from zero. Salifert tests. Rock solid zeros always, except for during cycling.

Why is that a problem? Doesnt that just mean my tanks are low nutrient? NO. I clean algae off my glass every 3-4 days. There is obviously, unarguably, NO3 in the water.

Even worse, take a look at those color charts. I've compared the kits. Can we stop fooling ourselves? The human eye isnt going to detect a difference between 0 and 5 on Salifert, or any other test I've looked at. A person can look at the chart and subjectively, based on their mood, the weather, and the lighting in the room, decide to mark down one number or another. But lets not kid ourselves. All we're really doing is saying "there is not much NO3 in my tank". We cannot tell the difference between 0 and 5, let alone 0 and 2, with these kits.

Is there a place for NO3 kits? Sure. Two places. Cycling and tanks where something is going wrong. I'd put these test kits right up there with Cu test kits: limited to very specific cases, not useful for daily or weekly testing.

In summary: in my experience NO3 tests appear to tell me nothing about the level of NO3 in my tanks. Still doubt it? I dose my tanks daily with 2 ppm nitrate (final concentration, calculated from mass and volume). And even after those doses, cant see any change in NO3.

I will be curious to hear feedback. Prove me wrong! I like testing and believe in water quality testing but I just do not see any evidence there is value to NO3 testing.

[I should add the caveat here that I have not explored Hanna NO3 tests; in principle a spectrophotometric assay has the ability to detect these low concentrations in an objective and reproducible way]

The fish are releasing ammonia from their gills almost constantly, & this is why algae grows on the glass. Along with urea. Algaes favourite foods.

Turtlesteve · 11/19/2018, 06:35 PM

I only have the normal range NO3 test kit (that reads in 5 ppm increments) and I might as well not test, it's always zero. Same for PO4. One day I'll break down and buy the hanna meters.

11/15/2018, 12:04 PM	#1
EMeyer Registered Member Join Date: Mar 2016 Posts: 173	NO3 testing confession and heresy OK, folks, I have to make a confession. I've stopped doing nitrate tests a long time ago. Some readers may find my reasoning obvious and wonder why I'm rehashing accepted wisdom. Other readers may find this crazy. Well, I have a crazier one for you. I dont believe the numbers people report on forums from NO3 tests mean anything whatsoever, unless something has gone very wrong and the tank has 20+ nitrates. So I think anyone keeping a healthy reef tank who is doing NO3 tests is probably throwing away money on these tests too. Here is the thing. In about 5 years of testing water in a series of 6 different tanks, I have never, ever, seen a nitrate level thats different from zero. Salifert tests. Rock solid zeros always, except for during cycling. Why is that a problem? Doesnt that just mean my tanks are low nutrient? NO. I clean algae off my glass every 3-4 days. There is obviously, unarguably, NO3 in the water. Even worse, take a look at those color charts. I've compared the kits. Can we stop fooling ourselves? The human eye isnt going to detect a difference between 0 and 5 on Salifert, or any other test I've looked at. A person can look at the chart and subjectively, based on their mood, the weather, and the lighting in the room, decide to mark down one number or another. But lets not kid ourselves. All we're really doing is saying "there is not much NO3 in my tank". We cannot tell the difference between 0 and 5, let alone 0 and 2, with these kits. Is there a place for NO3 kits? Sure. Two places. Cycling and tanks where something is going wrong. I'd put these test kits right up there with Cu test kits: limited to very specific cases, not useful for daily or weekly testing. In summary: in my experience NO3 tests appear to tell me nothing about the level of NO3 in my tanks. Still doubt it? I dose my tanks daily with 2 ppm nitrate (final concentration, calculated from mass and volume). And even after those doses, cant see any change in NO3. I will be curious to hear feedback. Prove me wrong! I like testing and believe in water quality testing but I just do not see any evidence there is value to NO3 testing. [I should add the caveat here that I have not explored Hanna NO3 tests; in principle a spectrophotometric assay has the ability to detect these low concentrations in an objective and reproducible way]

11/15/2018, 04:58 PM	#3
outssider Registered Member Join Date: Nov 2009 Location: Reseda, Ca. Posts: 1,717	red sea nitrate kit shows a big difference between 0-4 but you may be right because my tank always shows ZERO and I have to clean glass every 3-4 days too !!... (-0- P04 also) __________________ Please don't feed the bears because the bears will become dependent on free handouts and forget how to take care of themselves …... Current Tank Info: 75 Gal. Mixed reef mostly sps Last edited by outssider; 11/15/2018 at 05:35 PM.

11/15/2018, 09:26 PM	#4
EMeyer Registered Member Join Date: Mar 2016 Posts: 173	Red Sea kits. Interesting that some online images show a range of invisible to barely visible pinks like this https://*****.com/y946xnhx And others show a qualitative change from pale blue to pale pink http://wiki.aquatribu.com/images/7/7b/NO3-Red_Sea.jpg Thanks for the tip I will have to investigate further. I reached my conclusion based on the invisible to barely visible pink scale... which matches the other tests I'd used. [Am I misunderstanding something? ******** and ***** are both censored? Thatd be kind of odd. LOL, they are. OK nevermind.] Last edited by EMeyer; 11/15/2018 at 09:33 PM.

11/15/2018, 10:28 PM	#5
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Nitrate seems to be hard to pin down as to its effects. I don't see any reason to measure as long as the tank is doing well. I might consider measuring once every few months as a safety measure, but I didn't in the past. __________________ Jonathan Bertoni

11/15/2018, 02:07 PM	#2
Uncle99 Crab Free Zone Join Date: Sep 2017 Location: Ontario, Canada Posts: 2,906	I keep nitrates at 3ppm and do a water change at 5ppm. Both too much and too little make my corals unhappy.

11/19/2018, 06:35 PM	#7
Turtlesteve Registered Member Join Date: Nov 2001 Location: Upstate South Carolina Posts: 478	I only have the normal range NO3 test kit (that reads in 5 ppm increments) and I might as well not test, it's always zero. Same for PO4. One day I'll break down and buy the hanna meters.