Aquarium filtration and Chemicals

You can always read the values listed in the title (ammonium/ammonia - nitrite - nitrate). However, you may not know what you have to do, so here is a summary of the most important things to take into consideration.
1: Ammonium
Ammonium is a nitrogen compound and has the chemical formula NH4 +. This shows the chemist that it carries an electrical charge.
The water in the aquarium is/should be free of ammonium. It should have the same quality as drinking water and this is a basic prerequisite. Otherwise, the water is dirty and unhealthy. Aquarium water constantly contains ammonium. The departure of feces and urine and the decomposing remains of food are essential from this point of view.
Water plants are grateful for the ammonium in the water. They take it and use it as a nutrient source. Ammonium is relatively nontoxic, but unfortunately it influences the pH value. Ammonia is a gas, which can dissolve in water very well.
The conversion is a purely chemical process and is dependent on the pH value. The higher the pH, the faster can the ammonium be transformed into ammonia. This is why these values should be measured on a regular basis.
The same goes the other way around. If the pH value is low, the ammonia changes back into ammonium. A pH of 6.0 brings with it the assumption that there is only ammonium in the basin.
In summary, one can say that a relatively dirty aquarium (no regular water changes or too many fish) plus a high pH results in the lethal cocktail - ammonia.
Limits
Ammonium is harmless, but ammonia values ranging from of 0.02 mg/l are absolutely lethal to fish.
You may simply buy drop tests from stores to measure the values and react accordingly.
Normally, the values in the aquarium remain stable, but should any abnormality be detected, a partial water change will solve the problem.
2. Nitrite
Nitrite is produced by the oxidizing activity of the filter bacteria from ammonium. Nitrite has the chemical formula NO2. It is also one of the ions. This is why there is a minus in the formula.
Nitrite is fish poison, which is also fatal in higher concentrations. It disables the properties of oxygen in the blood. In general, nitrite is converted into nitrate very rapidly and thus it is again non-toxic to the fish. You must have good aquarium filtration so beneficial bacteria can develop in the filter.
Too little aquarium maintenance or too small a filter, as well as too many fish are usually the causes of high nitrite levels.
Limits
Fish can usually stand quantities of up to 0.1 mg/l without being harmed. Any value above this can be harmful or fatal.
If the values do not match, you must look into the cause. Not to mention an immediate change of water is in order.
Once again, there are various tests in shops so that you can measure the values.
3. Nitrate
The oxidation of the filter bacteria transforms nitrite into nitrate.
Nitrate has the chemical formula NO3-. Nitrate is a fairly stable nitrogen compound and represents the final stage of bacterial oxidation. Nitrate cannot be processed by ordinary aquarium filters and therefore can accumulate in the aquarium. Although some plants absorb ammonium, they prefer nitrate and there is usually more nitrate than the plants can use.
Nitrate is basically safe for our fish. But as always, there is a catch. Nitrate is converted into nitrite in oxygen-poor regions, but the reverse process can be fatal. Our drinking water is a nitrate limiting example. It contains 50 mg/l, but the average is much lower, of about 20 mg/l. The reason is that our body also has oxygen-deficient regions, which could be dangerous for young children at higher levels.
Limits
Discus breeders strive for values up to 20 mg/l. It was observed that young animals are exposed to sluggish growth at values higher than 40 mg/l. Normal adult animals grow up best with values up to 50 mg/l. But once again, you should remember that the nitrite-nitrate reaction could occur in both ways, one of them being very dangerous for the fish.
Again, there are several commercial tests for measuring the values.
The nitrate level can be lowered bets through a partial water change.
At the end, you can say that measuring the water values and regular water changes are among the most important tasks a successful aquarist should fulfill in order to keep healthy fish.Use an additional aquarium air pump if the water circulation is not enough.
So, enjoy as much good water as possible.