The need to reduce water hardness in the aquarium arises quite often. For example, if you decide to achieve spawning from neon, it is almost impossible to do it in hard water. Therefore, we will devote some time to available at home methods of reducing water hardness.
What is water hardness, what are its types and in what units it is measured – see here. What methods of determining hardness are the most acceptable at home, we have considered in this article.
Now let’s try to learn how to change the hardness of water for our needs.
What kind of water needs hardness reduction?
As previously stated, the hardness of tap water in most cities is acceptable for most freshwater fish species.
This is the case if the water is taken from a river. If the water is supplied from artesian wells, the water is likely to be more hard than is acceptable for us. And such water will need to be softened.
There are several techniques used to remove water hardness in the technique
- Thermal softening
- Reagent softening
- Reverse osmosis
Reduce water hardness by thermo-softening
Thermal softening is the normal boiling of water as a result of which calcium and magnesium hydrocarbonates, which are thermally unstable, decompose to form water insoluble compounds – scale.
Ca(HCO3)2 → CaCO3↓ + CO2 + H2O.
In this way we eliminate the hydrocarbonate (temporary) hardness of the water. This method of reducing water hardness is the easiest, safest and most acceptable for the aquarist.
Reagent softening – Adding chemicals to the water that convert calcium and magnesium salts into an insoluble state so that they precipitate. The reagents used are soda ash Na2CO3 or slaked lime Ca(OH)2. The following reactions take place
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3↓ + 2H2O
As you can see, the reaction with soda lime produces water (H2O) and water insoluble CaCO3.
This method can be used, but it has some difficulties. It is necessary to calculate the exact amount of reagent and weigh it accurately, and the precipitate must then be filtered. This is all justified in industry when treating large volumes of water. In the home with some experience can also be used, but the novice aquarist is better not to use it.
Reduce water hardness by cationization
Cationization is the use of ion exchange resins. Ionic exchange of calcium and magnesium cations for sodium and hydrogen ions takes place. It is used in industry to produce very soft water.
Reverse osmosis is a very interesting way to obtain very soft water in flowing mode. It is used in household water treatment systems for drinking water. It should be borne in mind that very soft water or completely desalted (distilled) is dead water! Eggs in such water can swell, plants can not grow in such water. I would not use such water in its pure form. But to dilute hard water to the desired hardness is quite acceptable.
Reduce water hardness by electrodialysis
Electrodialysis – removes hardness salts from water under the action of an electric current. The result is a reduction in water hardness.
So, having discarded all the methods associated with the use of electricity, accurate calculation of chemicals, the use of complex technological equipment, let’s take on board the rest. And what do we have left to influence the hardness of water in the aquarium?
Most aquarists use to soften water by boiling it. In this case, having boiled the water, letting it cool down and stand still, it is desirable to carefully drain the upper 2/3 of the water. And this drained water to add to the water that should be softened. In most cases, such softening is enough for the needs of the aquarist.
If the addition of boiled water does not reduce the hardness to the desired level, the water can be diluted with distilled water or water that has passed through a semi-permeable membrane. By increasing the volume of water with the same amount of salts, we reduce the hardness per unit volume.
Don’t forget to control the hardness of your water in one of the ways available to you, such as those described in this article.