ammonia/ammonium/nitrite/nitrate/cycling(in CC amphib glossary)

definition for these terms here. Particularly how they relate to each other.

ammonia (ammonium): a toxic product produced by uneaten food and feces in an aquarium. See [cycling].

nitrite: a toxic product of the breakdown of [ammonia] in an aquarium. See [cycling].

nitrate: a non-toxic (final) product of the breakdown of [ammonia] and [nitrite] in an aquarium. While not toxic, high levels of nitrate in aquarium water indicate the need for larger partial water changes on a regular basis. See [cycling].

cycling (1): The breakdown of waste products in an aquarium. Waste products produce [ammonia]. The subsequent activity of beneficial bacteria break ammonia into [nitrite] and then into [nitrate]. An aquarium is considered to be "cycling" (or "cycled") when the beneficial bacteria have become well established, a process that takes one month or more after a new aquarium has been set up. See [link to cycling article].

cycling (2): The seasonal changes that prepare an animal for reproduction. For example, a salamander may need to be exposed to a cold winter and decreased sunlight in order to be properly cycled for breeding in the spring.

This one looks good. Unless anyone has anything additional to add we could change it to ready.

That's a short version, but good to understand.
I would add the sum-formulas and that the reduction from ammonia (NH3) to nitrite (NO2-) to nitrate (NO3+) needs oxygen.

With too little oxygen in the water, nitrate can break down to (toxic) nitrite again, but that is a special case (can happen without light where plants consume oxygen, too).

Do we need to include the term "ammonium"? I rarely hear this used in the context of aquariums.

Here's a revised version:

ammonia: A toxic product (chemical formula NH3) produced by uneaten food and feces in an aquarium. See [cycling].

nitrite: A toxic product (chemical formula NO2-) of the breakdown of [ammonia] in an aquarium. See [cycling].

nitrate: The non-toxic product (chemical formula NO3) produced by the breakdown of [ammonia] and [nitrite] in an aquarium. While not toxic, high nitrate levels (>50 ppm) in an aquarium indicate the need for larger partial water changes on a regular basis. See [cycling].

cycling (1): The breakdown of waste products in an aquarium. Waste products produce [ammonia], which is subsequently broken down by beneficial in the presence of oxygen. The ammonia is converted to [nitrite] and then into [nitrate]. An aquarium is considered to be "cycling" (or "cycled") when the beneficial bacteria have become well established, a process that takes one month or more after a new aquarium has been set up. See [link to cycling article].

cycling (2): The seasonal changes that prepare an animal for reproduction. For example, a salamander may need to be exposed to a cold winter and decreased sunlight in order to be properly cycled for breeding in the spring.

I am fine with that.

"Ammonium" is used in german and means "ammonia". I don't know if there is an additional meaning in english.

ammonium is what ammonia reverts to at a lower ph(I believe under ph of 6.5). At this stage it is less toxic, and beneficial bacteria are not as active. A long overdue waterchange on a tank with water that has acidified due to lack of water changes will convert all the ammonium to ammonia...with consequences for the fish.

At least...that is how I understand it.

Joseph is right. There is free ammonia (NH3-N) and ionized-ammonia (ammonium) (NH4+-N) (both resulting from protein breakdown) which exist in an equilibrium. The amount of each in this equilibrium depends on pH -level and temperature. Whereas the ionized form is quite harmless and rather high concentrations are tolerated (at least by fishes) the free form is toxic for aquatic organisms. Lower pH - levels will result in an increase of the ionized form and vice versa. Basically the same happens with temperature drop respectively increase.

Okay, now that's a translation mistake - in this case your "ammonium" is called "ammoniak" over here.

My chemistry classes of long ago come stumbling back in consciousness... While this is all somewhat relevant to aquariums, it's hard to put into a concise definition.

Shall we omit "ammonium" from the definition? Or can anyone propose a definition that includes it?

I think we can leave it aside for now as it comlplicates the definition.

But then I also made a mistake with the formula: "ammonia" should be "NH4" instead of "NH3" (ammonium)

If we say that it's toxic should we name the levels it might get toxic at?
f.e.:
ammonia: readings higher than 0
nitrite: readings higher than 0
nitrate: readings should below 40/60

One addition:

cycling (1): The breakdown of waste products in an aquarium. Waste products produce [ammonia], which is subsequently broken down by beneficial bacteria in the presence of oxygen.

Click to expand...

It is correct to say that ammonia and ammonium exist in equilibrium in water but in actuality at all but the highest pH most ammonia (NH3) exists as ammonium (NH4+). Even in the lab ammonia solution is chemically ~ammonium to all intents and purposes.

OK, here is the final version, hopefully:



ammonia or ammonium: A toxic product (chemical formula NH3 or NH4+) produced by uneaten food and feces in an aquarium. The ideal ammonia level in a well-established aquarium is zero. See [cycling].

nitrite: A toxic product (chemical formula NO2-) of the breakdown of [ammonia] in an aquarium. The ideal level of nitrite in a well-established aquarium is zero. See [cycling].

nitrate: The non-toxic product (chemical formula NO3) produced by the breakdown of [ammonia] and [nitrite] in an aquarium. While not toxic, high nitrate levels (>50 ppm) in an aquarium indicate the need for larger partial water changes on a regular basis. See [cycling].

cycling (1): The breakdown of waste products in an aquarium. Waste products produce [ammonia], which is subsequently broken down by beneficial bacteria in the presence of oxygen. The ammonia is converted to [nitrite] and then into [nitrate]. An aquarium is considered to be "cycling" (or "cycled") when the beneficial bacteria have become well-established, a process that takes one month or more after a new aquarium has been set up. See [link to cycling article].

cycling (2): The seasonal changes that prepare an animal for reproduction. For example, a salamander may need to be exposed to a cold winter and decreased sunlight in order to be properly cycled for breeding in the spring.

I like this version. It reads better and seems a better fit.