Many people have been discussing which ammonia detoxifiers are best for use during cycling and for other circumstances like running sicks tanks. I thought it might be helpful to have something pinned for reference.
The following products detoxify ammonia whilst still leaving it available for use by the bio-filter. In other words they won't disrupt the nitrogen cycle.

Prime - Seachem
binds lower levels for up to 24 hours; after this time it will unbind if you have not changed water.
The standard dose detoxifies approximately; 0.8 mg/L ammonia,;1.2 mg/L chloramine; 3.3 mg/L chlorine.
It is possible to double dose if either amm or chlor's are high.
It can also be used to detoxify nitrite in an emergency; up to 5 times normal dose may be used in this instance.

NB. mg/L are more or less equal to ppm.

Caution:

Kits: Avoid Nessler kits (yellow to brown); they are completely disrupted by the active ingredients and will give you false 'off the charts' results.
Instead, use a salicylate based kit (yellow to green); the key to success is to take the reading right away, as the results will not be reliable after time in the tank.
The best solution of all is to use the Seachem MultiTest: Ammonia kit... it uses a gas exchange sensor system which is not affected by the presence of Prime or other similar products. It also has the added advantage that it can detect the more dangerous free ammonia and distinguish it from total ammonia (which is both the free and ionized forms of ammonia)

Amquel - Kordon
detoxifies ammonia permanently.
The standard dose; up to 3 mg/L chloramines; 1.0 mg/L of all ammonia compounds in fresh or salt water.
Use multiple doses to remove more than 1.0 mg/L ammonia from the water.

Cautions:

Kits:
As with Prime, a Nessler kit should not be used.
Salicylate kits are preferable with the exception of API which does not work either. The best option is to use Kordon's own brand Aqua-Tru test kits.

Meds:
As Amquel is, among other things, a dye remover, it should never be used in conjunction with treatments containing chemical dyes (such as methylene blue, acriflavine, potassium permanganate or malachite green) as AmQuel will interfere with their performance.

PH stability :
Under some circumstances (multiple doses at a low end PH) Amquel has been known to lower the pH in the water due to the acidity of its formulation; Kordon do make buffers specifically for use with this product.

Amquel +
Like Amquel, Amquel plus also detoxifies ammonia permanently.
The standard dose will detoxify at least 1.2 mg/L ammonia, at least 2.0 mg/L nitrites, at least 13 ppm nitrates. and amazingly, 33 ppm of all chlorines including those chlorines in chloramines from the water. Detox of compounds normally happens within five minutes, or slightly longer for ammonia in water with a higher pH above 7.5.


Cautions:

As for Amquel.

One exception; AmQuel+ does not affect the water's pH.



Ammo-Lock - API

Like Amquel, it detoxifies ammonia permanently.
Standard dose; 3mg/L ammonia (doubled dose - up to 6mg/L); 7 mg/L chlorine; 5mg/L chloramine.

Cautions:

As with the other conditioners, avoid Nessler kits.
API can also give off the chart ammonia readings.
I suspect a kit using the gas exchange sensor system would be more reliable than a colormetric tester, although I have not had this confirmed by API.
Its effect upon chemical dyes is currently unconfirmed by API. also - I will post up with any further info as and when I receive it.

I hope this info will be helpful.

Excellent information! Thank you Pixie!

I was hoping this would get pinned. This was sooo helpful to me. Thanx again Pixie!!!

Wow, thanks so much for this information! It is super helpful. I am getting a bunch of new goldies on Friday, and was getting prepped to set up a medicated quarantine tank, and this thread answered all my questions concerning how to keep ammonia levels under control!

Did you ever hear back from API concerning whether or not Ammo-Lock interferes with chemical dyes? For what it is worth, the website DrsFosterSmith.com, in its description of Ammo-Lock, explicitly says that it "can be used with all medications including Methylene Blue, Malachite Green, and Acriflavine." So it looks like Ammo-Lock will work great for my purposes.

It's scary that prime only binds ammonia for 24 hours or less; I use prime all the time, and now I worry that when setting up tanks or doing very large water changes, I might get a spike of unbound ammonia 24 hours later!

I know Pixie is gone for a while now, but I am curious about one thing. Trinket, if you read this, maybe you can help?

I've seen various people (including you Imogen) tell people NOT to use Ammo-Lock because if you do the tank will never cycle. But according to this post, Ammo-Lock does detoxify the ammonia, but still leave it in a form that is available to the bio-filter. Is there something about Ammo-Lock that I am unaware of that makes it not recommended to people?

I've used all three of these products..



I've found that in a fully cycled tank, Prime is perfect.. When doing large water changes, even with my tap water, which contains ammonia, the ammonia is gone well within 24 hours, therefore the Prime does the job perfect. I've also found that using it during a cycling tank is fine as well, because in a cycling tank you will no doubt be doing a large water change daily. So I usually do my water change every 24 hours (ish) and dose the entire tank.. I have used ammo-lock a few times in an emergency.. Not often, but if there is a night when I have been out ALL day and simply cannot do the water change. I believe this has happened only once or twice at most, but it was wonderful to have on hand just in case.. Personally I like the fact that Prime only binds for 24 hours. If you think about it, if the ammonia is THERE, you really should be doing a water change! Knowing that Prime only lasts for 24 hours gives me that extra push to get me off my butt and do that water change.. You basically cannot allow yourself to slack off, and that's good for me. That being said, I do love ammo-lock for those unpredictable situations.

Now, if I had ammonia straight out of the tap, I might think differently, but I, myself, prefer not to use any product that messes with my readings. I wanna know what I have, straight out. I just don't like to be left wondering what's true and what's not. I mean, I'm not a very trusting person, and so, I'm thinking, "is the ammonia REALLY gone or are my readings just telling me that?.... hmmm" And I don't want to have to worry and think, "okay, now what product did I use and what can and cannot be used with it." I might use something in some sort of desperate emergency, but not as a regular practice.

That said, this IS extremely informative and does really help me to know what to use when and if I do decide to use an ammonia detoxifier. Thanks Pixie!

Having ammonia in the tap water makes things tricky.. Like you said, I HAVE to use SOMETHING to detoxify the ammonia. Most times my ammonia straight out of tap reads 0.25. I HAVE seen it go closer to 0.50. It makes things very difficult if the tank isn't cycled. In a cycled tank, it's not so much of a problem. Like I said, I can add prime to the tap water, add THAT water to the tank and everything is back to zero the next day. In a cycling tank it's so much harder. I try to keep my ammonia as close to 0.25 as possible, and use the prime every 24 hours so I can hopefully assume that whatever IS in there, is in non toxic form. But the tricky part is, say I do a reading and it's 1ppm. (I'll use that because it's a nice even number). Most people could do a 75% water change, and assume their water is down to 0.25ppm. But that's not the case when you are adding BACK tap water with ammonia which at times is 0.50. This is why I do a lot of 100% water changes in my tanks WHILE they are cycling. I figure with a fresh batch I KNOW what's in there. The good thing is, it seems that for the most part the tests go over, not under. Every time I have used ammo lock, I take the readings and they go up REALLY high. I have to assume it's false. For this reason I tried out the seachem ammonia meters. They seem to be really accurate as a backup..and supposedly read FREE ammonia. I've put one in a bucket WITH prime treated water, and it shows zero free ammonia. I've also put one in a bucket straight from tap, and it shows that there IS in fact free ammonia.. I now keep one of those in all my goldy tanks as a back up. Pretty much, to be safe, when I have a cycling tank, I tank ammonia readings just to keep a log, but almost always do a 75% water change each day and a 100% water change every few days, just to be safe.