A “Protein Skimmer” is a well-known marine aquarium-based tool that helps keep water clean from pollutants.
Each marine aquarist knows very well the result of a good foaming, a dark-smelling liquid in the collection cup.
This liquid contains a mixture of many substances that have been removed from the aquarium’s water and is the product of a decomposition in a concentrated form that releases bad smells.
Foaming is predominantly composed by proteins, in which are the amino acids, containing sulfur such as methionine, cysteine and homocysteine.
These substances are necessary for bacteria, which are also foamed by the aquarium, as nourishment.
During this process, bacteria consume so much oxygen to form an anaerobic, oxygen-free environment in the cup.
In the container there are processes through which the bacteria get energy from the sulfur containing compounds, reducing them into hydrogen sulphide (H2S).
Hydrogen sulphide is the culprit of the stench of a collection cup of your skimmer.
Hydrogen sulphide is a toxic gas, which even with a dilution of 500,000 times is olfactory appreciable.
This can be avoided, so it is necessary to inhibit bacterial activity.
What can you put in the collection cup of your skimmer to avoid the odor?
You can introduce the so called “Kalkwater“(Kalwasser in Deutschland) , which is a liquid containing calcium hydroxide Ca (OH)2 in saturated solution, which increases the calcium value in the water and increases the pH.
A high pH value is mortal for most bacteria by greatly inhibiting metabolism.
The hydrogen sulphide contained in the water reacts and is dissolved thanks to the alkaline environment avoiding the gaseous and ammonia formation.
To increase the pH value in such a small volume, just a few drops of a saturated calcium hydroxide solution are enough.
If the foam is poured back into the water, there is no problem because the amount of calcium hydroxide present in the glass is negligible.
Smell defeat and more happy wives!