What Amquel Will Do For Your Tank

Submitted by "daryl"

I have been looking at the use of the product Amquel, as a shipping aid, an aid in controlling emergency situations in a fish tank, an aid in maintaining an overcrowded tank for a short time and as a regular maintenance regiment for a populated, cycled tank. There seem to be a myriad of beliefs, cautions, facts, and fears surrounding this product, and its uses. These I hope to examine in closer detail, to perhaps clarify the way this product works and how you can make it work for you.

Amquel will detoxify chloramines, chlorine, and heavy metals from tap water as needed. For this purpose it is a fine product, but its abilities to bind ammonia are what I will examine here. There are many products on the market which handle the chloramines, chlorine and metals alone. Since you may not wish to have Amquel affect the ammonia in your tank, you should perhaps consider using another water conditioner for just the chloramines, chlorine and metals.

As a quick review, the nitrogen cycle is what we refer to as a "tank cycle", or a healthy tank. Goldfish produce ammonia as waste, which is converted to nitrite by the Nitrosomonas bacteria. The nitrite is, in turn, converted to nitrate by the Nitrobacter bacteria. This nitrate is then either reduced by regular water changes, which dilute it to a concentration tolerated by the fish, or is used by plants and algae as food. Without the proper bacteria to convert the ammonia to less toxic compounds, the tank can quickly become toxic to fish, leading to fish loss.

(Figure 1) The Nitrogen Cycle
NH2 + O2 + Nitrosomonas bacteria = NO2 + H2

(ammonia) (oxygen) (nitrite) (hydrogen ions)
NO2 + O + Nitrobacter bacteria = NO3 (Nitrite) (oxygen) (nitrate)

(Figure 2)Amquel Bottle

(Amquel-How It Works, n.d.)

The active ingredient in Amquel is sodium hydroxymethanesulfonate or HOCH2SO3Na. The hydroymethane end of the molecule is the one that is used to detoxify ammonia. (The -sulfonate end is used to react with chlorine and chloramines.) Amquel traps the ammonia by binding it into a chemical compound along a carbon/hydrogen bond. The spare oxygen and hydrogen can be released as water (H2O) or oxygen and free hydrogen ions. The nitrogen that is bound in such a fashion is still available on demand to the Nitrosomonas bacteria that utilize it to create nitrites. (Unreacted Amquel is stable and will remain in the water until removed by water changes or by activated carbon. Activated carbon will not remove Amquel that has already bonded with ammonia.)

First, let us examine the use of Amquel when shipping fish. A fish is transported in water that contains no bacteria to detoxify the fish's wastes. The Amquel will bind the fish's waste ammonia, releasing hydrogen ions and oxygen into the water. Since there is nothing to take the ammonia from the Amquel, the Amquel will eventually lose its usefulness when it can carry no more ammonia. Also keep in mind, that since there are no Nitrosomonas bacteria available to use the ammonia, no nitrites are manufactured and the cycle ends here. Nitrite is not produced and the ammonia is technically removed from the fish's environment. The water is rendered non-toxic. (The subject of pH will be discussed at the end of this article)

As a shipping aid, Amquel does an outstanding job of detoxifying fish waste for a limited amount of time, dependant on the amount of Amquel that is placed in the shipping water. (Amquel is non-toxic to fish, even in large quantities, so a longer trip could potentially be made safe by a larger amount of product being added to properly buffered shipping water.) Along this same line, it is also good as an aid to detoxify an un-cycled hospital tank, since, after it binds the ammonia, the cycle ends.

Amquel can be used to control an emergency situation in a toxic tank, but should be viewed as simply an emergency "band-aid" for the situation. If, through any number of reasons, your tank has toxic amounts of ammonia in its water, this ammonia can be bound with Amquel to a non-toxic form within five minutes of introduction to the tank. "Great!" you say, "The ammonia is gone." But you need to realize that it is not. It is simply currently in a non-toxic form. The ammonia has not been removed from the water. Instead, it has simply been converted into a larger, stable and non-toxic compound (aminomethanesulfonate), free oxygen and hydrogen ions. (See figure 2) This bound ammonia is still available for the Nitrosomonas bacteria to utilize to convert to nitrite in the regular cycle of the tank.

Rather than liberally dosing a toxic tank with Amquel, more importantly the reasons you have toxic levels of ammonia need to be examined if you wish to rectify a problem tank. Is your fish load too high for the number of bacteria you have available in your biological filter so they are unable to break down all the waste produced? If this is the case, the Amquel will only delay a toxic situation. You have not avoided the toxic tank, for you have not removed the ammonia at all. Amquel easily releases its load of ammonia to the Nitrosomonas bacteria, which will, in turn, continue to use this nitrogen, producing nitrites. But do not forget that your fish are still producing more ammonia all the time. All the ammonia can be potentially used to produce nitrites, though this is highly unlikely, for, if the Nitrosomonas bacteria could not handle the load before, they certainly cannot handle greater amounts. Constant additions of AmQuel are needed to just barely keep up with the ammonia load.

Amquel will bind up the ammonia in an emergency situation, rendering the ammonia wastes non-toxic but it does not address the nitrites. Unless the numbers of Nitrosomonas bacteria and the numbers of Nitrobacter bacteria are greatly increased, the fish load is greatly decreased, very large, regular water changes are done, or large regular additions of Amquel are used, the situation will quickly become just as or more toxic than before. Do not count on Amquel to keep tank detoxified by itself, on a regular basis. It cannot handle it. Keep in mind that the Nitrosomonas bacteria will be pumping nitrites into your fish's environment as fast as they can, using all the newly created ammonia as well as the ammonia that Amquel has removed. Nitrites could spike tremendously, for the Nitrobacter bacteria are less efficient at converting nitrites to nitrates than the Nitrosomonas bacteria are at making nitrites and will not be able to keep up with the excess nitrites.

Amquel in an overcrowded tank will, with the help of frequent and large water changes, keep the ammonia levels down to a tolerable level. Binding the ammonia and then removing the bound ammonia/AmQuel through water changes will effectively delay problems. It should not, however, be viewed as anything more than an aid to alleviate a temporary situation, and, as discussed above, cannot do the entire job by itself.

Along this same line, Amquel has limited uses in a balanced, cycled tank. It does not harm your cycling bacteria, for it will not, contrary to popular myth, starve your bacteria by removing all the ammonia from the environment. A well cycling tank will remain a well cycling tank. The ammonia it removes from the water is still readily available to the bacteria to utilize in their cycle. Even if you greatly overdose, the Amquel simply stays available until ammonia is present. It will not prevent the Nitrosomonas bacteria from using the ammonia it binds.

The pitfall of Amquel is that regular use can lead you into a false sense of well-being, for your tank may not be truly cycling on its own. If you regularly add Amquel, and it keeps the ammonia under control, you may think your tank is balanced. You must realize, however, that if you need the Amquel, your Nitrosomonas bacteria are not available in sufficient numbers to do the whole job. You may think they are, for you have zero ammonia readings, but those readings will quickly change if you stop using the Amquel, and doing good water changes. This is where the myth that "once you use it you must always use it" seems to come from. Your tank is not truly cycled if you need Amquel to maintain the zero ammonia readings. Stop using it and you will have an ammonia spike. The Amquel has not killed or harmed your cycle, nor has it stunted it. It merely has obscured the fact that your cycle is not sufficient to handle all that is in your tank.

Example: Your fish produce 10 units of ammonia. The bacteria reduce 5 units of ammonia to nitrite, and Amquel reduces 5 units of ammonia by binding it. Your test says you have no ammonia. Your nitrites are being converted to nitrates. All looks good. You change the water regularly and add more Amquel. You assume your cycle is working well. But without Amquel, your fish still produce 10 units of ammonia, the bacteria still reduce 5 units to nitrite, but now you get a reading of 5 units of ammonia. Your cycle was not taking care of the waste but you did not know this and assumed it was working. The bacterial cycle did not crash or die, it simply was never there in the needed abundance - a fact that Amquel can hide.

One last consideration must be taken when using Amquel as an additive. As shown in the chemical equation at the beginning of this article, (Figure 2), Amquel takes the ammonia and releases oxygen and hydrogen ions into the environment. This is much the same as the Nitrosomonas bacteria releasing hydrogen ions when it converts the ammonia to nitrite (Figure 1). Under the best circumstances this is released as water (H2O) as shown in Figure 2. More often, however, it is released as separate oxygen (which is good) and hydrogen ions. Just like in the regular nitrogen cycle, these released hydrogen ions can cause the pH to drop significantly if the proper buffer is not available in your water. But, unlike the Nitrosomonas bacteria, Amquel can release the hydrogen ions in a matter of minutes, as opposed to hours or days. If you are detoxifying a high concentration of ammonia, you potentially could crash your pH within minutes, leading to great fish loss. Proper buffering is essential, and pH should be checked every time. Leave nothing to guess work - do the real work and check it! It could avert a disaster.

All in all, Amquel is a fine product for shipping, detoxifying hospital tanks, or any situation where there is no bacterial cycle working. It has limited uses in an emergency or an unusual situation such as a seriously overcrowded tank, but should not be considered a product for regular everyday tank maintenance.

Post Script: I have been seeking formulae for AmQuel Plus, and the older product AmQuel Dry. The former is a newly introduced product designed to "Remove Nitrite, Nitrate, Ammonia, Chlorine & Chloramines" as well as "fishes" toxic pheromones". It is purported not to affect the pH of a tank. Because it is "patent pending", the formula is not being released, however I suspect that it works much the same as AmQuel works, with an added buffer. If this is true, then it, too, is a fine product. Other than the tendency to obscure biological cycle effectiveness, a product that can reduce nitrites and nitrates might be very useful! I will report when I have additional information.

References 1. AmQuel . Retrieved July 24, 2003 from
2. AmQuel - How It Works . Retrieved July 24, 2003 from
3. Johnson, Erik & Hess, Richard. (2001). Fancy Goldfish . Trumbull, CT: Weatherhill, Inc.