How does Prime work? - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 22 Old 11-22-2012, 10:04 PM Thread Starter
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How does Prime work?

A knowledgeable keeper explained to me that Prime detoxifies ammonia (NH3) by adding a hydrogen ion, thus converting it to ammonium (NH4). I assumed, because ammonium cannot exist in a pH >6.5 or so, that it loses this ion and converts back to ammonia---faster, if the pH is higher.

However, on the Seachem Prime site, I came across this:
" Prime works by removing chlorine from the water and then binds with ammonia until it can be consumed by your biological filtration (chloramine minus chlorine = ammonia). The bond is not reversible and ammonia is still available for your bacteria to consume. Prime will not halt your cycling process."

The italics are mine. This oversimplified explanation does not square with my admittedly rudimentary understanding of the chemistry involved.

Can anyone set me straight?
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post #2 of 22 Old 11-23-2012, 06:10 AM
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So what's your question? :D

Chloramine is NH2Cl so when the Chlorine (Cl) is stripped there is still Ammonia to deal with, which another chemical in Prime will make into Ammonium (NH4) regardless of pH for a period of ~24-48 hours. The Chlorine will never 'un-bind' and forever be 'safe' for the fish.

That 24 to 48 hours is usually long enough for bacteria, or plants, to consume it and thus no longer be a problem.

This is only if your water has Chloramine, if your water uses regular old Chlorine then no ammonia is formed, the Chlorine is just binded and the ammonia detoxifying chemical is doing nothing. This is a reason to consider not using Prime so you don't add chemicals that are not needed.
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post #3 of 22 Old 11-23-2012, 08:44 AM
Thanks for the chemical type explanation of prime.

One of the considerations is to test a tank for ammonia then treat for that ammonia one time only per instructions.

Or as I prefer to just add fast growing live plants to consume the ammnoia quickly.

What can happen is that you add prime (or other dechlor/ammonia locks) then test for ammonia and find ammonia is still there. Because most test kits (exclucing the seachem multi test ammonia kit) test do not distinguish between the dangerous free ammonia and safer locked ammonia.

So still having ammonia you add more prime and repeat.

All the while that first test locked up all the ammonia and all subsquet doses were unnecessary.

And all dechlor/ammonia locks have bad side effect such as locking up oxygen. So you can wind up suffocating your fish which gives the same symptoms as ammonia.

So IMHO the best thing for the fish is to simple start the tank with lotsa fast growing plants. That way ammonia is rapidily consumed which also reduces carbon dioxide and returns oxygen. So that each 24 hour period the tank actually becomes a net consumer of carbon dioxide and producer of oxygen. Then as the tank matures and ammonia is consumed by bacteria, the plants get their nitrogen from the resulting nitrates. And if something goes bump in the night later the plants rapidily consume any ammonia spike breaking up not only that spike but possible crashes as well.

my .02

maintain Fw and marine system with a strong emphasis on balanced, stabilized system that as much as possible are self substaning.

have maintained FW systems for up to 9 years with descendants from original fish and marine aquariums for up to 8 years.

With no water changes, untreated tap water, inexpensive lighting by first starting the tank with live plants (FW) or macro algae( marine)

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post #4 of 22 Old 11-25-2012, 08:24 AM Thread Starter
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Thank you both for your considered replies. But my question remains unanswered.

The treatment of the chloramine and the treatment of ammonia are more properly dealt with separately, as Geomancer has done. I believe chlorine can forever be "bound," but I'm not sure that adding a hydroxyl to ammonia to create ammonium is a permanent change or why that should be.

API's explanation seems to concatenate these two processes, so their answer is more confusing than helpful. In their very next sentence, API admits to not understanding how Prime detoxifies nitrite. Admitting this on their company website, while admirably honest, does nothing to enhance their credibility when explaining other processes.

Nor do they detail why their ammonia-to-ammonium effect lasts 24 to 48 hours. That 100% margin of error makes me wonder what else they can't or won't explain.

I know about converting ammonia to ammonium; about salicylate test kits reading all NH3/4 as free ammonia (NH3); about percentage of free ammonia relative to pH.

But what happens to the all that ammonium? Surely it doesn't remain ammonium at 7.6pH.

Last edited by Hallyx; 11-25-2012 at 08:43 AM.
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post #5 of 22 Old 11-25-2012, 08:50 AM Thread Starter
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I am great admirer of aquatic gardeners; dirt gardeners, as well. Unfortunately, some of us lack that certain feeling when it comes to green, growing things. I'm lucky to be able to achieve and maintain a secure and stable nitrogen cycle for the health of my fish. I can keep Anubias alive. That's about it.

People like beaslbob and OldFishLady and Byron, who have the capacity and feeling to grow things, are truly blessed.
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post #6 of 22 Old 11-25-2012, 09:53 AM
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the ammonia/ammonium ratio is usually pH dependent, what Seachem is implying is that their product converts ammonia to some compound other than ammonium that is harmless, stable and can still be acted on by nitrogen cycle bacteria
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post #7 of 22 Old 11-25-2012, 11:51 AM
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I have corresponded with Seachem on the issue of Prime so perhaps this rather simple explanation may help. I told them I was not a chemist and didn't want to get bogged down in convoluted equations, so they kept it simple for me.

Prime "detoxifies" ammonia, nitrite and nitrate by binding them somehow. In the case of ammonia, it becomes ammonium, which is basically harmless. Nitrosomonas bacteria will use ammonia or ammonium, whichever is present, and live plants the same [plants prefer ammonium as their nitrogen source, and have the ability to take up ammonia and convert it into ammonium]. As for nitrite and nitrate, Seachem stated they are not really certain how this works themselves, but there is some sort of binding. And here again, bacteria can still take them up.

Second, Prime is effective for a limited period. Seachem suggested 24-48 hours, with 36 hours perhaps being safer. The idea behind using Prime if you have ammonia, nitrite or nitrate in the source water (or in the aquarium as during the initial cycle) is that it will render all three harmless for 24-36 hours. If the substances are still present after this period, they will "unbind" so to speak, and become toxic. But in a normal balanced aquarium the plants and/or bacteria should be able to handle the ammonia/nitrite/nitrate introduced in the source water at a water change by the time Prime wears out. In new cycling tanks, additional water changes using Prime perhaps daily will be needed until the bacteria is established sufficiently to handle the ammonia and nitrite. But here, if live plants are present in sufficient quantity with some fast grtowers, they will be able to deal with the ammonia [with a minimal fish stocking obviously] and nitrite is not a byproduct with plants, which is why live plants in new tanks are so important.

The chlorine and chloramine is a bit different; it remains detoxified.

A final few words on the ammonia/ammonium. The pH does affect this. At an acidic pH, below 7, the ammonia naturally occurring from fish respiration, breakdown of organics, etc will be in the "safe" ammonium form. Plants and bacteria will take it up. But the fish will not be affected because it is ammonium. But in a basic pH, above 7, it remains ammonia [except when Prime or a similar product is present]. So if Prime is used and the pH is above 7, the ammonia is bound into ammonium for 24-36 hours, after which it will "unbind" back into toxic ammonia in the basic pH.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

Last edited by Byron; 11-25-2012 at 11:56 AM.
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post #8 of 22 Old 11-25-2012, 12:10 PM
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The thing about chemistry is that it's not black and white. You can still have ammonium in your water at pH 7.5, and you can still have ammonia in the water at pH 6.5. These things work more in ratios.
Here's a cute little graph I found as an example:

The legend shows what your classic test kit would read, and the value of "true free ammonia" is the amount of NH3 actually in the water..

In regards to temperature.. I'll take a guess and say at higher temperatures, ammonium levels rise. Prime does say to use less in temperatures over 86F.

All I can say is Prime is a mystery.

taking a break from fish-keeping.
3 lovely male betta still keep me company.
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post #9 of 22 Old 11-25-2012, 12:17 PM
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If all prime did was covert ammonia to ammonium by adding a proton, it would have to be due to pH change and the resulting ammonium would be subject to further changes in pH.

I've never used Prime, but I assume the instructions or packaging makes no mention of the product affecting pH or that it's effects are only seen at certain pH levels so this suggests that something other than simple ammonia to ammonium conversion is occurring and that whatever compound is created is not pH dependent as is NH3/NH4+
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post #10 of 22 Old 11-25-2012, 12:17 PM
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double post
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