Analyzing Hanna Ammonia checker Hi784, chemistry and performance

[taricha]

Hanna's saltwater ammonia checker, Hi784 is out and I wanted to take a look and assess its performance for reef tank water, and see where some interpretation of results might be helpful. This post will include some data on a display tank processing ammonia, and in a later post I'll do a comparison of accuracy vs ammonia stock additions.

Checker specs

Range	0.00 to 2.50 ppm (mg/L) NH3 [to clarify, it's actually NH3+NH4]
Resolution	0.01ppm
Accuracy @ 25°C/77°F	±0.05 ppm ±5% of reading @ 25 °C (77 °F)
Light Source	Light Emitting Diode @ 610 nm
Light Detector	Silicon photocell
Method	Adaptation of the Salicylate Method. The reaction between Ammonia and Ammonium and the reagent causes a blue‑green tint in the sample.

This (like the other chemical tests - API, red sea etc.) is a total ammonia test using salicylate method.
The other common ammonia detection method in the hobby is the Seachem ammonia alert badges, multi-test disks and seneye, which all use gas-permeable membranes to measure NH3 only. Calculation of toxic free ammonia, NH3 from the hanna total ammonia test involves using a table of pH and temp like what's included in the hanna checker manual



These are the %'s to multiply the total ammonia reading by to calculate toxic free ammonia, NH3.

Using the kit, you'll find it's very much like the API test. The first liquid drop reagent contains the salicylate and nitroprusside compounds that makes up the thick yellow/brown drops, and the last liquid drop reagent is the high pH additive, sodium hydroxide and the hypochlorite, again like API. The "new" bit that makes it work for a hanna checker is the powder reagent B added between the two liquids, it's a chelating agent to prevent cloudiness that would cause the checker color measurement step to fail.
( @Dan_P posted how to do this using sodium citrate to keep the API test clear and run it in a hanna checker at 610nm a year and a half ago.)

The cloudiness-killing step is essential, and if cloudiness forms in your sample by the end of the 15 minute hold time - from not enough reagent B, or salinity too high - then don't bother with the checker step, cloudiness will read nonsense high.


The first performance question to talk about is results on perfectly stable tanks. Measurements of mature stable systems seem to generate values in the 0.1-0.2 ppm range. Here's @SaltwaterAq measuring 0.19ppm total ammonia on a healthy mature system, and my display that consistently runs zeros on NO3 (and all other inorganic N forms) measured 0.15, and 0.14 (not near feeding times) on two different days.
Since a stable mature system is almost everybody, some clarity here is helpful as to whether our tanks are actually generating a couple of tenths of total ammonia by constant churn of remineralization of food, or if this is simply a test kit artifact.

A simple way to illuminate this is how a mature system handles a known several tenths ppm of ammonia and compare to what the hanna checker is seeing. So I added an expected ~+0.50ppm total ammonia to my display (carefully measured, I already know how my system consumes ammonia, and it was at pH at 7.8, so no real hazard here)

(lots of ammonia-consuming surfaces between the display and the lighted sump)


Blue stars show the baseline measurement, and red shows the values while the spiked ammonia is being consumed.




Here you can see a few features.
1) the expected spike of +0.5ppm ammonia is well measured (actual calibration curve in a later post when I get more reagents).
2) the depletion trend is consistent, and the checker captured very well the mechanics of what's going on.
3) the consumption rate is consistent with the idea that actual ammonia is consumed rapidly in a tank like this: in fact the consumption rate is pretty steady at 0.5, 0.4, 0.3 down to 0.2 ppm ammonia. It makes very little sense to suggest consumption suddenly stops at 0.15ppm.
Instead it is far more likely that the detected 0.1-0.2ppm ammonia that people are measuring is simply a test kit artifact, and very unlikely that tanks deplete ammonia rapidly from 0.5ppm to 0.2ppm then just stop.

This phantom couple of tenths total ammonia will be very familiar to anyone who's seen a bunch of API tests.

Below is what the reacted tests on clear tank water looks like for test results measuring 0.15 ppm.



Notice that both API and hanna generate this blush of "not-quite-yellow" color that people (and now the checker's digital eyeball) misinterpret as an ammonia detection. This is simply an artifact of the test kit chemistry. Compare to what a genuine detection of ~0.5 ppm ammonia looks like below. There is no confusion or ambiguity.


There are some chemistry details on the formation of this low level test kit artifact (it's not just people's bad eyes getting fooled), but I'll save it for later.
The short answer is to simply interpret 0.1-0.2ppm readings as zero baseline the same way a slight blush of green on API should be read as zero.

Calibration data for the Hanna Kit is here in post #10

 

[brandon429]

Ten star thread coming. Glad to see what unveils. Glad you're doing this test, we're hungry for ammonia data

100% subbed

Please test for adulteration possibility with either prime or amquel/ very common unspoken additives in many cycle challenges.

 

[brandon429]

T

Based on your sum interaction with this meter and seneye, can you comment on any links or disparities between the two meters such as drop rate/ nitrification rate timing, bottom end measures, just anything you recall between the two meters you've used

 

[taricha]

Based on your sum interaction with this meter and seneye, can you comment on any links or disparities between the two meters such as drop rate/ nitrification rate timing, bottom end measures, just anything you recall between the two meters you've used

The total ammonia chemistry (hanna, Red Sea, API etc) gets fooled by some organic N compounds to a certain degree. For instance it measures about 1/4 of each mole of glutamine and glutamic acid as a mole of ammonia. (source: data from Dan)
It can also get fooled in the negative direction by any reducing compounds like Prime, thiosulfate, or ClorAm-x.
It is excellent and sensitive if you know what you're measuring is actually ammonia (cycling etc).

The NH3 sensing gas permeable films (seachem alert, multi-test disks, seneye) are very hard to fool. I do not know of any compounds in hobby tanks other than ammonia that get by and register as NH3. Also I know of no way to negatively interfere with them when there is real ammonia around. The films are susceptible to physical damage and will generate false positive color if the films are compromised.
The films are also harder to do very low detections with, because the color is subtle. Seneye bypasses this with a sensitive method using automated reflectance at 2 (I think) wavelengths. Downside is your eye can't detect the changes in the film that the automated unit can. So you can't doublecheck the seneye. You can just pull the cuvette out of the hanna checker and look to see if it's green or not.

That's a long way of saying if you know you are measuring ammonia, the total ammonia chemistry is great for trending it. If you don't know, and it could be interference, then nh3 films are the better choice. They are much harder to fool.

More details on seneye I'll defer to @Dan_P who actually worked with the unit.

 

[Dan_P]

The total ammonia chemistry (hanna, Red Sea, API etc) gets fooled by some organic N compounds to a certain degree. For instance it measures about 1/4 of each mole of glutamine and glutamic acid as a mole of ammonia. (source: data from Dan)
It can also get fooled in the negative direction by any reducing compounds like Prime, thiosulfate, or ClorAm-x.
It is excellent and sensitive if you know what you're measuring is actually ammonia (cycling etc).

The NH3 sensing gas permeable films (seachem alert, multi-test disks, seneye) are very hard to fool. I do not know of any compounds in hobby tanks other than ammonia that get by and register as NH3. Also I know of no way to negatively interfere with them when there is real ammonia around. The films are susceptible to physical damage and will generate false positive color if the films are compromised.
The films are also harder to do very low detections with, because the color is subtle. Seneye bypasses this with a sensitive method using automated reflectance at 2 (I think) wavelengths. Downside is your eye can't detect the changes in the film that the automated unit can. So you can't doublecheck the seneye. You can just pull the cuvette out of the hanna checker and look to see if it's green or not.

That's a long way of saying if you know you are measuring ammonia, the total ammonia chemistry is great for trending it. If you don't know, and it could be interference, then nh3 films are the better choice. They are much harder to fool.

More details on seneye I'll defer to @Dan_P who actually worked with the unit.

I will just add that ammonia sensing colorimetric films can be photographed and the color intensity measured with color analysis software. This will get you close to the Seneye sensitivity. Better still is to use a spectrophotometer to analyze the reflected light from the sensing film. In this way you can check up on Seneye. These methods require consistent lighting.

I did not find any substance that colored the films but I did find that all films fail to fully recover from ammonia exposure over time. This means they will begin to indicate ammonia when none is present. Seneye is one of the better at recovering but still degrades and needs to be replaced regularly.

 

[Malcontent]

What reading do you get if you run the test procedure on ammonia-free water?

The Hach test requires zeroing with a blank created by adding the reagents to ammonia-free water (which I found out can be surprisingly difficult to obtain).

 

[brandon429]

I will re read these posts for max comprehension and enjoy doing so. Thanks Taricha and Dan for a thread many folks will benefit from.

 

[brandon429]

There's one interesting characteristic of your test tank that's very different from all other displays, I don't think it affects outcome/ ammonia command at all but it's a unique presentation among reef displays.


What's the one thing missing in that pic above of a finely aged reef that all other display reef pics show?


Live rock

none spotted in display (due to system age and corals overtook)

That's actually the lowest functional surface area display I've seen. What it may lack in hardscape surface area contact compared to a Saxby stack wall from 2011 it makes up for in living tissue surface area I believe will have direct command for ammonia out of the water. Nitrifiers / clades that reduce ammonia for us whatever the genus/ are covering all those fleshy areas. Collectively that's an ammonia- scrubbing reef anyway without lots of live rock.

Most reefs are bone opposite: stacked rocks and tiny coral nubs.


(Of course any plumbed in surface area may not be apparent/ if you have a sump etc)

Ammonia is in high, high demand within our tanks is what I take from the timed ammonia drop chart above.

 

[taricha]

Ammonia is in high, high demand within our tank is what I take from the timed ammonia drop chart above.

yes. That is the point I was getting at. Established well-lit tanks would gobble up any ammonia at rates well exceeding its production. The tenth or two total ammonia detected doesn't seem realistic.

Live rock

none spotted in display

Big rock-pile cave/tower is on the un-pictured half of the tank.

but back to topic...

What reading do you get if you run the test procedure on ammonia-free water?

The Hach test requires zeroing with a blank created by adding the reagents to ammonia-free water (which I found out can be surprisingly difficult to obtain).

The tank water basically is ammonia-free. It's probably possible to do some more sensitive versions of a total ammonia test and show that the tank water reading 0.15ppm is actually < 0.05 ppm. Regardless, almost all of the 0.1-0.2ppm reading that people are getting from hanna is non-ammonia artifacts.

When I wanted to generate a hard zero water source for ammonia testing I would take a liter or two of tank water, add a sprig of algae, a drop of ethanol, a teaspoon GAC, and bubble it in the light for a day. It was low enough, that adding +0.02ppm ammonia was easily detectable.
I'll run the hanna test on water treated that way, and update.

 

[taricha]

Here's a look at calibration run on tank water treated for a couple of days to strip as much possible ammonia and organics that could interfere and give slight ammonia results.

To calibrate / compare the Hanna test to known concentrations of ammonia I did separate stock solutions with ammonium sulfate and ammonium chloride, and ran a series of concentrations with each added to the saltwater.

As a check, I used a modified API test that @Dan_P came up with and has been my go-to for ammonia tracking for a couple of years now. (5mL sample, 3 x 0.15mL scoops of sodium citrate dihydrate, 4 drops of Reagent A, 3 drops Reagent B).

Hanna in blue, the modified API recipe in red. the series of X's is with ammonium chloride, the diamonds are ammonium sulfate.
[disregard the "NH3". Hanna says they report the amount of total ammonia-nitrogen detected in units of NH3, even though almost all of it will actually be NH4 in solution. So the calculations reflect that.]

The Hanna is very linearly responsive across the entire range up to 2.5 ppm. The slopes are all very close to 1, so the combined error between my stock making and the hanna checker is <8%. Excellent.

The Hanna chemistry is also very responsive at the lowest concentrations, even additions of +0.025, and +0.06ppm registered as higher on the checker. Below is a zoomed in graph of the same data as above, illustrating the low - range behavior.

Looking at this I would absolutely trust the hanna checker to detect the difference between saltwater, and the same saltwater with +0.05ppm ammonia added. But based on the above, I do not think the hanna test is capable of telling whether tank water has 0.0 ammonia or 0.1-0.2ppm ammonia in it.

The issue with the high baseline is not optics/electronics of the checker - it's the chemistry itself. Looking at the reacted samples without the checker, just measuring the absorbance at 610nm (where the checker measures) in a spectrometer there's a "high zero."

This high baseline is actually still there even if you run the sample on pure De-ionized water (I used a bottle of DI from hanna) or a 70/30 mix of DI and my saltwater zero - green and yellow stars.
This is because it doesn't come from the sample. It comes from the reaction of the test chemistry itself - hence Hach's instructions mentioned earlier to use a reacted zero-ammonia sample as a source.


Here's the raw absorbance of the reacted tests on the low levels...

Here you can see the high baseline that the hanna test has, and that the hanna "blank" does not come close to correcting it away.
This is why in the modified API test, Dan reduced the reagent amounts to just above the minimum needed to make the reaction proceed fully, doing so turns down the interfering color to very low, reduces the baseline correction to almost none and makes detections of <0.05 very simple. The trade-off is a one hour reaction time.

Bottom line:
Hanna's test is consistent, fast, and very sensitive to changes in ammonia within the same water. It can not tell you if your reef water has zero or 1 to 2 tenths ppm ammonia, and any values reported in the range of ~0.2ppm or similar should be interpreted as clean zero.

 

[brandon429]

what a detailed review. appreciated

 

[Dan_P]

Here's a look at calibration run on tank water treated for a couple of days to strip as much possible ammonia and organics that could interfere and give slight ammonia results.

To calibrate / compare the Hanna test to known concentrations of ammonia I did separate stock solutions with ammonium sulfate and ammonium chloride, and ran a series of concentrations with each added to the saltwater.

As a check, I used a modified API test that @Dan_P came up with and has been my go-to for ammonia tracking for a couple of years now. (5mL sample, 3 x 0.15mL scoops of sodium citrate dihydrate, 4 drops of Reagent A, 3 drops Reagent B).

Hanna in blue, the modified API recipe in red. the series of X's is with ammonium chloride, the diamonds are ammonium sulfate.
[disregard the "NH3". Hanna says they report the amount of total ammonia-nitrogen detected in units of NH3, even though almost all of it will actually be NH4 in solution. So the calculations reflect that.]

The Hanna is very linearly responsive across the entire range up to 2.5 ppm. The slopes are all very close to 1, so the combined error between my stock making and the hanna checker is <8%. Excellent.

The Hanna chemistry is also very responsive at the lowest concentrations, even additions of +0.025, and +0.06ppm registered as higher on the checker. Below is a zoomed in graph of the same data as above, illustrating the low - range behavior.

Looking at this I would absolutely trust the hanna checker to detect the difference between saltwater, and the same saltwater with +0.05ppm ammonia added. But based on the above, I do not think the hanna test is capable of telling whether tank water has 0.0 ammonia or 0.1-0.2ppm ammonia in it.

The issue with the high baseline is not optics/electronics of the checker - it's the chemistry itself. Looking at the reacted samples without the checker, just measuring the absorbance at 610nm (where the checker measures) in a spectrometer there's a "high zero."

This high baseline is actually still there even if you run the sample on pure De-ionized water (I used a bottle of DI from hanna) or a 70/30 mix of DI and my saltwater zero - green and yellow stars.
This is because it doesn't come from the sample. It comes from the reaction of the test chemistry itself - hence Hach's instructions mentioned earlier to use a reacted zero-ammonia sample as a source.


Here's the raw absorbance of the reacted tests on the low levels...

Here you can see the high baseline that the hanna test has, and that the hanna "blank" does not come close to correcting it away.
This is why in the modified API test, Dan reduced the reagent amounts to just above the minimum needed to make the reaction proceed fully, doing so turns down the interfering color to very low, reduces the baseline correction to almost none and makes detections of <0.05 very simple. The trade-off is a one hour reaction time.

Bottom line:
Hanna's test is consistent, fast, and very sensitive to changes in ammonia within the same water. It can not tell you if your reef water has zero or 1 to 2 tenths ppm ammonia, and any values reported in the range of ~0.2ppm or similar should be interpreted as clean zero.

Neat!

Do you think the Hanna zero can be fixed?

 

[taricha]

Neat!

Do you think the Hanna zero can be fixed?

You can mostly fix it by just reacting the test on RODI and using that as the blank.

Red line on bottom is reaction on DI water, 2/3 of the high baseline at 610nm is removable that way.

I probably won't trial and error it to work out an improved recipe to fix the other 1/3 of the baseline, when I can just subtract 0.11ppm from the checker with this batch and declare victory.

 

[Randy Holmes-Farley]

Thanks for the nice review and testing!

 

[zwandz]

Finding this today makes me feel less crazy. I’ve been using this checker for a few weeks and always get around .15 - but everyone is extremely happy and growing, so I let it go and considered it a baseline. The first time I even used API against it. I have coral only and feed twice a week - never mattered if it was before or after, or before or after a water change.

 

[taricha]

Finding this today makes me feel less crazy. I’ve been using this checker for a few weeks and always get around .15 - but everyone is extremely happy and growing, so I let it go and considered it a baseline.

Glad it was helpful. Seems like that will be typical.
It's a little in the weeds for just a test kit discussion, but since most people will get that result, I figured I'd talk about why.
Your choice to consider it the baseline and move on was correct. There's nothing you can do to your water to drop it to zero.

 

[MnFish1]

Every test has an accuracy and precision. Personally - for the cost - I would not use the hanna checker - Nor - any reason to use it - BUT - the calibrations/testing here is valuable. I have never had an ammonia test - except during the studies I did.

 

[brandon429]

Mn

I'm concerned that it does not read zero

calibrated seneyes read zero on tenths ppm nh3 99.99% of the time after setup according to the rules, their logs show.

and I have yet to see a single 0 read on hanna, to align with the seneye posts en masse. so that leaves hanna in question, not seneye in my opinion.


**if it's utility to indicate change is accurate/sensitive then that makes up for a poor baseline assessment in my opinion, for $59 total dollars invested it can be used to make or refute cycling proofs.

I think seneye's bottom line reading is more accurate based on the myriad posts showing no real toxic impact from claimed ammonia events in reef, we naturally run far away from the risk line in my opinion (because we all mimic the same surface area to volume to circulation ratios pretty much)

 

[Garf]

Mn

I'm concerned that it does not read zero

calibrated seneyes read zero on tenths ppm nh3 99.99% of the time after setup according to the rules, their logs show.

and I have yet to see a single 0 read on hanna, to align with the seneye posts en masse. so that leaves hanna in question, not seneye in my opinion.


**if it's utility to indicate change is accurate/sensitive then that makes up for a poor baseline assessment in my opinion, for $59 total dollars invested it can be used to make or refute cycling proofs.

I think seneye's bottom line reading is more accurate based on the myriad posts showing no real toxic impact from claimed ammonia events in reef, we naturally run far away from the risk line in my opinion (because we all mimic the same surface area to volume to circulation ratios pretty much)

But you advocate the corrupting of the seneye data by calibrating out the accuracy. All seneye info I’ve read sais the slides are most accurate when new, then decline in accuracy through the month. However, it’s the inaccurate data you say should be used to calibrate the new slides to. This makes ZERO sense to me.

 

[brandon429]

If that's your takeaway from the posts your read Garf, ok then.

Taricha finds and reviews an inherent, plain, clear-as-day shock absorber system for ammonia in a reef tank (his cycle data was as appealing to me as his hanna test kit data)

we are making use of Taricha's findings here in cycle study threads without having to worry which digital kit is more accurate, I simply feel that reef tanks trend to the lower end of nh3 control, the thousandths ppm, and the greater chemistry forum apparently believes wide ranges are acceptable. that conflict makes for the evolution of reef tank cycling science. I have always stated I felt that calibrated seneyes run in the thousandths ppm nh3, it's what their scrolls of posted logs show/ its a summary of what I've seen.