Short version: Does Prime have formaldehyde in it? Interesting Q, but pointless regardless because formaldehyde doesn't protect from ammonia even if it does react - the hypothetical product is toxic in aquaria conditions, and it looks likely it doesn't react with ammonia in aquaria anyway.
This is a rebuttal of sorts that I found on another forum. It will probably kill a few brain cells.
A BIG THANK YOU to @Guppysnail and @Odd Duck for this concept, for the editing of this article and for reviewing it for accuracy and errors! A Brief History of Prime® An abbreviated history of dechlorinators and detoxifiers and their evolution Discussions on whether dechlorination and detoxificat...
forum.aquariumcoop.com
As
@Dan_P said, much of the underlying references are irrelevant (papers about what H2S, UV-A, Ozone, etc do to ammonia, reactions that happen with ammonia inside living organisms etc. )
But I'm apparently a glutton for punishment, so I thought this was interesting. And it is the chem forum so sifting through confusing and messy data is some people's idea of a good time.
That test from the above article seems to be an airborne Formaldehyde test like
this one.
If the author simply held Prime nearby and detected formaldehyde, this might be a proper detection. If they did something less rigorous like adding a drop of Prime directly into the reaction liquid, then they might have just decomposed something else into formaldehyde. (It's not said which was done.)
Seachem contemplates formaldehyde in other people's products, but doesn't confirm or deny formaldehyde in it anywhere I could find.
@Randy Holmes-Farley has
explained the role that formaldehyde would play in the proposed reaction of ClorAm-X that is expected to bind Ammonia.
(None of what follows is relevant to Prime if it doesn't actually have formaldehyde in it. I expect it is still relevant to ClorAm-X etc.)
This paper from 1978 analyzed the actual products in the reaction between formaldehyde and ammonia at 25C using NMR, so it would seem fairly ironclad that such a reaction actually occurs at room temp.
Structure and chemistry of the aldehyde ammonias. 3. Formaldehyde-ammonia reaction. 1,3,5-Hexahydrotriazine (abstract only)
@Malcontent had shared this paper about using formalin to detoxify ammonia for catfish and shrimp (fresh and saltwater) earlier
in the thread.
They found the ratio of formalin to ammonia that's needed to react all the ammonia, then they used that ratio of formaldehyde to treat ammonia running up to 2ppm total ammonia.
What they concluded was that even though the ammonia was gone, fish and shrimp still died - thus the ammonia-formaldehyde product is still toxic (their conclusion.)
But they never compared ammonia+formalin to just ammonia without formalin. And their test for if the ammonia was in fact reacted away by the formaldehyde was ..."Ammonia concentration was determined by method recommended by Grassholf (1976)" - which if you look up that text, is in fact the salicylate total ammonia test.
So an alternative interpretation consistent with their data is that maybe the formaldehyde didn't actually react away the ammonia in the first place.
After reading that paper, I checked what 2ppm ammonia did with Formalin in their recommended dosage.
It kills off the total ammonia test to zero, but shows no reduction on the NH3 films.
Looks like one of two things could be going on that would be consistent with all the data I'm aware of:
One: Is it plausible that formaldehyde does react with ammonia, produces a compound that can still pass through the gas-permeable NH3 sensing films, fooling the films into thinking NH3 is unreacted, and the compound also is still toxic to aquatic life so the whole stupid thing is moot whether it binds it or not?
Or two: Is it more likely that the reaction between formaldehyde and ammonia is not actually a slam dunk in aquaculture settings, and the paper measuring the products with NMR was reacting ammonium hydroxide with formaldehyde in conditions (pH, concentration) that is different enough from aquaria, that perhaps those reactions in fact don't really occur for us to any great extent.
There is a 1995 paper that I think addressed the question really well.
"Tolerance to Formalin by a Fluidized-Bed Biofilter and Rainbow Trout Oncorhynchus mykiss in a Recirculating Culture System" see attached pdf.
They actually looked at the question of whether formaldehyde interferes with the test methods.
"Effects of formaldehyde on TAN (Total Ammonia Nitrogen) measurement by the Nessler method, the
salicylate method (using the Hach spectrophotometer), and an ammonia probe (Orion model 95-12) were also tested, by addition of 100 ppm formalin to one of a pair of samples of fish tank water before analysis."...
"The Nessler method was found to give an intense yellow color and erroneously high ammonia values in the presence of formaldehyde. Measurement of paired water samples with and without addition of 100
ppm formalin yielded 1 7.6 and 1.14 mg/L TAN (total ammonia nitrogen), respectively.
The salicylate method failed to detect TAN in the presence of formaldehyde, giving readings of 0.0 and 1.0 mg/L TAN for paired samples with and without addition of 100 ppm formalin, respectively. However, ammonia probe measurements were not affected by 100 ppm formalin, indicating that ammonia and formaldehyde did not react under the conditions in the system."