A Deep Dive on Ammonia Neutralizer Chemistry - Prime, ClorAm-X, Rongalite and friends.

[Formulator]

The paper mentioned earlier tested them.

Yes, but the same paper somehow also showed that Prime removes ammonia, so I’m a little skeptical now.

 

[Randy Holmes-Farley]

Here's a related question worth testing at some point...there is a filter pad called poly filter that claims to remove ammonia, among other things. It would be interesting to test if it actually does...I've been using it when bagging fish in an attempt to reduce ammonia levels in the bagging water and I am intrigued to know whether that actually helps.

It doesn't. it also doesn't remove phosphate, despite the claim. I am an expert on these two topics, outside of reefing, and have developed polymers to do both in other contexts that, at least in the case of phosphate, have sold billions of dollars worth.

No organic polymer can do either one from seawater. There is far too much competition from similar ions that are present at vastly higher concentration (say, chloride and sulfate for phosphate; sodium, potassium, etc for ammonium).

Note that the company does not actually claim it does these things in seawater, and any charged polymer can remove them from fresh water without competing ions.

 

[Malcontent]

Yes, but the same paper somehow also showed that Prime removes ammonia, so I’m a little skeptical now.

It should be easier to test since I think a standard salicylate-based total ammonia test should work. Just as you could measure ammonia removal by zeolite using that method...

 

[jft]

So Then Polyfilters CAN REMOVE PO4 in freshwater so would be useful to pretreat water before salt addition if RO DI water NOT available Correct? Randy. Thanks.

 

[Randy Holmes-Farley]

So Then Polyfilters CAN REMOVE PO4 in freshwater so would be useful to pretreat water before salt addition if RO DI water NOT available Correct? Randy. Thanks.

Yes, potentially. But the amount bound depends on how much is there, what pH, and what the competing ions present are. I'd be more inclined to use GFO in that context.

For a polyfilter, I'd be more interested in its ability to bind copper.

 

[jft]

Yes, potentially. But the amount bound depends on how much is there, what pH, and what the competing ions present are. I'd be more inclined to use GFO in that context.

For a polyfilter, I'd be more interested in its ability to bind copper.

ok thank you!

 

[Malcontent]

Another study:

http://drumandcroaker.org/pdf/July1982No2.pdf#page=24

 

[Dave101]

Wait prime has formaldehyde and they don't mention that ANYWHERE?

Yes. Because formaldehyde is used in embedding dead people. It kills off the bacteria that cause the spike in ammonia. 1 reason why is say ot is not good and will.only place a bandage on the main problem.

 

[Randy Holmes-Farley]

Yes. Because formaldehyde is used in embedding dead people. It kills off the bacteria that cause the spike in ammonia. 1 reason why is say ot is not good and will.only place a bandage on the main problem.

Are you being sarcastic? Or are you really claiming that Prime contains so much formaldehyde (despite Seachem’s claim it contains none) that it rises to the level needed to kill bacteria in the tank?

That is clearly not the case based simply on the dose used, even if it is concentrated formaldehyde.

 

[Dave101]

Are you being sarcastic? Or are you really claiming that Prime contains so much formaldehyde (despite Seachem’s claim it contains none) that it rises to the level needed to kill bacteria in the tank?

That is clearly not the case based simply on the dose used, even if it is concentrated formaldehyde.

I NEVER said that. Someone on here said that. All I was saying it kills and prevents bacteria from growing. I never like using products like Prime to control ammonia bc you are not solving the problem. I am saying is Prime is a bandage. To solve the high ammonia problem, you would need to look at the food, are you overfeeding, are you doing enough waterchaanges, also are you doing your weekly waterchanges? This will sovle the ammonia problem long term is what I am saying.

 

[taricha]

Literally. People are always complaining about the smell of Prime.

assuming this wasn't just a ruse to get me to sniff a bunch of formaldehyde, I opened my product bottles - they had been opened a similar number of months ago.

Fritz ACCR: contains HMS, no odor
ClorAm-X (similar concentration) I left out for a few days: contains HMS, no odor
Aqueon Ammonia Neutralizer : contains rongalite, strong sulfur smell
Prime : contains HMS & rongalite, same strong sulfur smell

My guess is that Prime gets blamed for the odor, because its one of the few products that has rongalite in it.

None of those had a noticeably strong smell when I first opened them. I expect it's the fact that they do react slowly with O2 causing some of the degradation and thus smell.

 

[taricha]

Yes, but the same paper somehow also showed that Prime removes ammonia, so I’m a little skeptical now.

It helps to read these papers with skepticism cranked up to max.

The paper mentioned earlier tested them.

and drum roll....it found they didn't do much (the authors refer to the poly-filters as ion exchange filters later in the paper).

 

[Formulator]

It helps to read these papers with skepticism cranked up to max

As a published scientist myself, this paper really bothers me. What is the motive for a university researcher working with NSF grant money to falsify results? Just afraid to question Seachem’s label claim? Or worried it would discredit the rest of the work? Like if Prime was supposed to be their positive control for ammonia removal and it didn’t work, that could call into question the rest of their work maybe?

 

[taricha]

previously, Parts 3 & 4

Parts 3 and 4 lay out the chemical properties of HMS and rongalite, so in part 5 I can describe how to test for them, what was found, and why the products don't work even though the chemicals used actually do theoretically bind ammonia. If you wish to look at nothing else, Fig 11 is the crux of the matter.


Part 5: Why do other products not work? Measurements of product ingredients

It is possible to use titrations to independently measure both the dechlorinating portion and the formaldehyde portion of the various aquarium ammonia removal products, and thus work out with a fair degree of confidence, what the likely composition of these products might be.

The basis for formaldehyde detection is the reverse reaction from equation (1) repeated below.

If formaldehyde, HCHO is present then adding excess Sulfite will cause the above reaction to go to the left, form HMS and create NaOH. You can then titrate for the amount of OH- produced and thus determine the amount of formaldehyde that was present. Brown [4] indicates that the test "can be used to detect any ketone or aldehyde but is sensitive to formaldehyde because of its high reactivity." The technique used followed this published guide [9] and was scaled down to 1mL test sizes. It requires only 1M sodium sulfite, 0.10 N sulfuric acid for titration and thymolphthalein as the indicator.
The only remaining obstacle to using this titration to measure the formaldehyde in the ammonia removal hobby products is that they are already a system of equal parts sulfite/sulfoxylate and formaldehyde, so adding excess sulfite does nothing. The workaround is that the sulfite or sulfoxylate in the products as dechlorinators can rapidly react with chlorine and end up as sulfate leaving behind free formaldehyde that can then be titrated for. In fact, sulfite/sulfoxylate themselves can be measured by titration against a fresh bottle of household bleach (7.5% Clorox Bleach is essentially exactly 1 Molar).
To track the bleach titration, an ORP probe and pH probe can be used. The ORP probe is highly sensitive to the bleach and dechlorinators: while there is excess dechlorinator, the ORP is kept low and once all the dechlorinating sulfite/sulfoxylate has been used up, excess bleach remains and the ORP will shoot up by hundreds of mV. Monitoring pH during this process adds additional information, because according to equation (1) again, freeing sulfite from the HMS to dechlorinate consumes a OH- and thus lowers pH. Using a standard base such as 1M NaOH, additions can be made precisely to balance the pH drop and thus measure the amount of base consumed in the process of dechlorination. These three measurements together: dechlorinator, base destroyed by dechlorination, and formaldehyde left over - can distinguish clearly between the various reducing sulfur compounds of interest that might be present in the ammonia removal product.
The table below shows the results (averages of 2 or 3 well-behaved replicates) of titrations using the above described methods.

Table 2. Various standards are listed in the first four rows. 10% neutral buffered formalin, 1M sodium sulfite, 1M sodium thiosulfate, 1M HMS (from solid ClorAm-X) were measured using the above described titrations for formaldehyde and dechlorinator. There is very good agreement between the measured stoichiometry (green data) and that expected from the standard (red.)
The bottom three rows are the measurements for liquid aquarium products: Aqueon Ammonia Neutralizer (lists rongalite as ingredient), Seachem Prime, and Fritz A.C.C.R. In the bottom four rows, the stoichiometric mole ratios are expressed in terms of ratio to formaldehyde, HCHO.

In practice, for these titrations - the standards were diluted to 20mL with distilled water and measured with ORP and pH probes while autostirring such that it took around ~2mL of 1 Molar bleach to complete the reaction totally. The amount of 1M NaOH needed to undo the pH drop was added gradually during the bleach titration. After the bleach titration was complete (ORP spike) and the pH had been brought back to near the initial value, then a few tenths of a mL of the bleach-dechlorinator neutralized solution were used in titrations for the amount of formaldehyde. The data in the above table for the undiluted products was calculated based on these volumes and dilution corrections.

The 10% neutral buffered formalin is a standard for the formalin titration alone, and the measurement agrees closely with the expected value of 3.7% formaldehyde (converted to moles).
The equations that predict the ratios in the “expected theoretical” column for the standards are given below.
For 1 mole of sulfite, equation (2) repeated below predicts a ratio of 1 mole of bleach, and no base effect, (also no formaldehyde)

For 1 mole of thiosulfate, equation (4) below [10] predicts 4 moles of bleach and 2 moles of lost hydroxide (no formaldehyde).

For 1 Mole of HMS, equations (1) and (2) together predict 1 mole of bleach, 1 mole of removed hydroxide, and 1 mole of released formaldehyde.

For 1 Mole of rongalite, the stoichiometric ratios differ from HMS only in that the sulfoxylate can react with 2 moles of bleach instead of the 1 mole of bleach that sulfite reacts with. Some sources [6] suggest that this happens by the hypochlorite reacting with rongalite to make HMS, while others [8] suggest that the reaction might be hypochlorite converting free sulfoxylate to sulfate. Regardless of the pathways, a mole of rongalite reacts completely with 2 moles of bleach, removing 1 mole of hydroxide, and freeing 1 mole of formaldehyde. Titration of the Aqueon A.N. product that claims rongalite as the ingredient agrees very closely with these ratios.
Note the relationship that for both HMS and rongalite, there is equal base removed for each formaldehyde liberated. Dechlorination with sulfite alone removes no base, and thiosulfate removes 2 base for each 4 bleach reacted. If we look at the measurements of Prime (multiple bottles, multiple replicates) the ratios are squarely between those for HMS and those for rongalite, suggesting it is a mixture of the two. Similarly titrations of Fritz ACCR have ratios that are a mixture of HMS and thiosulfate.

To further add confidence to the assertion that Prime is a mixture of HMS and rongalite, here’s what a comparison bleach-ORP-pH titration looks like between Prime and a mixture of HMS+rongalite.
The Prime was 1.00mL diluted to 20mL with saltwater. The “homemade Prime” is 0.85mL of 1M HMS + 1.65mL of Aqueon rongalite, diluted to 20mL with saltwater. Saltwater was used as the dilution to limit the effect of unequal buffering between the products (slight differences in the pH swings in fig 10b).

Figure 10a (top): The bleach-ORP titration has two phases. During the first phase, requiring approximately 55mM of hypochlorite, the rongalite reacts with the bleach even at medium to low pH. The second phase, comprising the rest of the ~100mM hypochlorite additions is the reaction between the HMS and the bleach at higher pH.
Figure 10b (bottom): The pH simultaneously measured during the bleach titration. Keeping the pH <7 for the first phase and raising it only for the second phase allows you to react the bleach separately with the rongalite first, and then the HMS in the second phase.

To describe more thoroughly the stoichiometry implications of what is shown in the graphs, the first phase is bleach reacting with rongalite, during this phase there is ~55mM of hypochlorite that is reacted and ~25mM of hydroxide needed to be added for balance - in close agreement to the 2:1 ratio in table 2 for rongalite. Once that phase is complete, the ORP spikes up because the hypochlorite additions do not react quickly with the HMS remaining - until the pH is raised. So the second phase has spikes up and down as each addition of NaOH releases sulfite from HMS which reacts with the hypochlorite and drops the ORP. This phase takes about ~45mM of hypochlorite, and ~40mM of hydroxide - in close agreement to the 1:1 ratio in table 2 for HMS. Both rongalite and HMS have an expected 1:1 ratio between the base that needs to be added and the formaldehyde present, and again there is a very good match. The total hydroxide added is 62.5 to 65 mM, and the formaldehyde titration results listed in the top right corner show that 62.5 to 66.3 mM formaldehyde was measured. All these close agreements with expected stoichiometry are good evidence for Prime containing the mix of HMS and rongalite described here. (Not shown, but a similar exercise was done with Fritz ACCR, which matches a mixture of HMS+thiosulfate.)

Because we have measurements of the molar concentrations of formaldehyde freed by bleach neutralization for the products in table 2 and HMS and rongalite each contain 1 formaldehyde, this is equal to the molar concentration of HMS or rongalite for each product. And thus we can now compare the relative ammonia remover concentration of each product and attempt to explain why ClorAm-X (but not other products) can show detectable ammonia removal with allowable label doses.

Table 3. The recommended dosage of each is quantified in terms of the amount of HMS or rongalite present - which determines the ammonia removal potential. In the far right column, the amounts of HMS + rongalite are calculated for the maximum label-allowed usage of each product.

The middle column is the calculation of how many recommended doses of each product it would take to equal 1x recommended dose of ClorAm-X. These values range from 7.3 doses for Prime to 0.96 doses for Fritz ACCR - indicating the Fritz basic recommended dose is intended to be the same as that for ClorAm-X. We can now revisit Fig 3, which shows the ammonia removal measured vs the amount of HMS, and use the trend to chart how the maximum allowable dose of each product compares to this trend.

Figure 11 (based on Fig 3): The maximum label-allowable dosage of each product (red notation) is charted by how much actual HMS or rongalite that dose contains, and thus how much ammonia removal at 48 hours one might expect to observe, based on the data trend. The arrows show approximately where each would fall along the measurement trendline.

Fig 11 illustrates that for the maximum label-allowed dose of Prime (and Aqueon A.N.), there is nowhere near enough HMS or rongalite to expect any detectable decrease in ammonia. The ClorAm-X dose being the highest, puts the amount of ammonia removal right at the edge of possibly detectable - if measured very carefully.

To tie up one last loose end, we should check the comparisons in Table 3 between ingredient concentrations, and the expectation that a mole of rongalite and HMS might have similar ammonia removal ability, based on the mechanism laid out in the thesis by Brown[4]. For that purpose - ammonia removal ability of ClorAm-X, Aqueon A.N. and Prime were compared using product doses that should contain HMS or rongalite equivalent to 20x ClorAm-X.

Figure 12. 2ppm total ammonia was measured after 24 hours with 20x dose of ClorAm-X, or an equivalent amount (in moles) of HMS + rongalite in each product, based on Table 3. All products showed similar modest amounts of ammonia removal, with the uncertainty probably too large to say any were actually significantly different.

From this data it seems that the products with rongalite (Aqueon) or a rongalite + HMS mix (Prime) remove ammonia similarly to HMS alone, or at least are not significantly better. So the trend of ammonia removal in Fig 11 can be thought of as an acceptable estimate for how these other products could remove ammonia as well, if label dosages were greatly exceeded.

(in two days, the end - I swear - Part 6: Extras - Overdose toxicity concerns, nitrification effects. Test method interference.)

Part 6: Extras - Overdose toxicity concerns, nitrification effects. Test method interference.

References
1. EPA. (2000). Wastewater technology fact sheet dechlorination. Environmental Protection Agency.
https://www3.epa.gov/npdes/pubs/dechlorination.pdf

2. Song, S., Ma, T., Zhang, Y., Shen, L., Liu, P., Li, K., ... & McElroy, M. B. (2021). Global modeling of heterogeneous hydroxymethanesulfonate chemistry. Atmospheric Chemistry and Physics, 21(1), 457-481.

3. Kuhns, J. F. (1987). Method and product for removal of chloramines, chlorine and ammonia from aquaculture water. U.S. Patent No. 4,666,610. Washington, DC: U.S. Patent and Trademark Office.

4. Brown, K. H. (1999). Kinetic studies on the reaction of formaldehyde with amines in the presence of sulfite (Doctoral dissertation, Durham University).

5. Danehy, J. P., & Zubritsky, C. W. (1974). Iodometric method for the determination of dithionite, bisulfite, and thiosulfate in the presence of each other and its use in following the decomposition of aqueous solutions of sodium dithionite. Analytical chemistry, 46(3), 391-395.

6. Gunter, R. (1988). Agent for the elimination of active chlorine compounds from water. U.S. Patent No. 4,786,434. Washington, DC: U.S. Patent and Trademark Office.

7. Makarov, S. V., Horváth, A. K., Silaghi-Dumitrescu, R., & Gao, Q. (2016). Sodium dithionite, rongalite and thiourea oxides: chemistry and application.

8. Wikipedia contributors. (2024, May 14). Sulfoxylic acid. In Wikipedia, The Free Encyclopedia. Retrieved June 2024, from https://en.wikipedia.org/w/index.php?title=Sulfoxylic_acid&oldid=1223734514

9. Garrick, A. (2009) Formaldehyde Determination by Sodium Sulfite Method. Oregon Department of Environmental Quality

10. Wikipedia contributors. (2024, May 26). Sodium thiosulfate. In Wikipedia, The Free Encyclopedia. Retrieved June 2024, from https://en.wikipedia.org/w/index.php?title=Sodium_thiosulfate&oldid=1225820101

 

[Malcontent]

So, was Seachem saying that Prime contains "complexed hydrosulfite salts" a red herring?

 

[Dan_P]

So, was Seachem saying that Prime contains "complexed hydrosulfite salts" a red herring?

I have wondered how product claims and information are developed for public consumption. It seems there is a kernel of truth in claims embedded in a fruit of obfuscation, but like seedless grapes, some claims are without that kernel of truth. Are these lies or mistakes? Proving intent to deceive the consumer is difficult, even with the number of Seachem’s seeming baseless claims about Prime. I will give them the benefit of the doubt though because the entire world seems to have gotten the ammonia removal/detoxification science wrong.

 

[Randy Holmes-Farley]

I NEVER said that. Someone on here said that. All I was saying it kills and prevents bacteria from growing. I never like using products like Prime to control ammonia bc you are not solving the problem. I am saying is Prime is a bandage. To solve the high ammonia problem, you would need to look at the food, are you overfeeding, are you doing enough waterchaanges, also are you doing your weekly waterchanges? This will sovle the ammonia problem long term is what I am saying.

I’m not going to argue with you about what you wrote or didn’t write as long as we agree that there’s no possibility that any additive to control ammonia in aquaria works by killing bacteria.

 

[taricha]

As a published scientist myself, this paper really bothers me. What is the motive for a university researcher working with NSF grant money to falsify results?

I don't see anything unethical in these aquaculture papers.
They believe that a salicylate total ammonia test is functional in the presence of HMS, and there's nothing in the Hach documentation that clearly indicates otherwise.

I mostly blame Hach, lol. If they'd listed formaldehyde and formaldehyde-containing compounds as interferents in their total ammonia test, then we wouldn't have decades of aquaculture papers using a total ammonia test when what they needed is an ion-selective electrode.

 

[taricha]

So, was Seachem saying that Prime contains "complexed hydrosulfite salts" a red herring?

It's actually not a bad description.
check this bit from the Danehy Iodometric paper [reference 5]

in other words, dithionite a.k.a. hydrosulfite, is split and then grabbed by formaldehyde into a 1:1 ratio of hydroxymethanesulfinate and hydroxymethanesulfonate or rongalite and "HMS" in my write-up. Which is the Prime ingredients.

For simplicity and elegance, I wanted Prime to be a 1:1 ratio of HMS and rongalite, because it means that process (reacting formaldehyde and dithionite) is the literal origin story of Prime, but the ratios are off. It's heavier on HMS, and lighter on rongalite. closer to 1.5:1

 

[Randy Holmes-Farley]

What a boatload of work, taricha!