Especially if your considering breeding particular tropical fish, it is always better to understand the chemistry of your aquarium. Total hardness, also known as GH, may not be considered if you’re new to this hobby but in order to avoid difficult issues that may arise in future, it’s always better to at least know what it is before something happens.
Table of contents
What is total hardness
This is the total amount of temporary hardness which is bicarbonate hardness (calcium and magnesium) plus permanent hardness (sulphate and chloride in associated with calcium and magnesium). Measurement of this total hardness is ppm that is a short of “parts per million” and it also is expressed as mg/L (milligram per litre).
If the test kit reads total hardness as high, the water is HARD while it is SOFT when total hardness is low.
Purpose and reason for measurement
Aquatic Plants
For growing aquatic plants perspective, there is certain total hardness desired for plants to thrive. Many aquatic plants in the market prefers slight acidic water but as mentioned above, pH will be more alkaline when total hardness is high. Hence plants don’t like the environment with higher total hardness.
Rocks and gravels used to decorate the layout especially for planted tank tends to increase the total hardness due to calcium and magnesium from them. Soil on the other hand, adsorbs calcium and magnesium so this can balance your total hardness to certain levels.
The adsorbability of soil will decrease over the period of time which leads to increasing the total hardness gradually. When it happens, you will either have to reset from the scratch or purchase the product that will reduce the total hardness.
Breeding Fish
From fish breeding perspective, total hardness takes a significantly important role for particular species. It is well known to the fish that prefers soft water (eg. Discus) affects negatively towards their willingness of spawning and hatching rate of eggs and vice versa to the species that prefers hard water (eg. African Cichlids).
What causes total hardness to change
Factors to increase total hardness
- Rocks and Gravels
- Injecting CO2
Rocks and gravels increase the total hardness by their calcium and magnesium
Total hardness will increase further more especially when you inject CO2 where rocks are introduced to aquarium for layouts.
Factors to decrease total hardness
- Soil
- Using product
As mentioned earlier, soil adsorbs certain levels of calcium and magnesium hence it balances total hardness value even when small amount of rocks and gravels are introduced. Although having said that, its adsorbability decreases as the time pass.
When it comes to this stage, you should consider either to re-start your aquarium or use the product to soften the total hardness of water. Using product to soften water is quick way of balancing total hardness whereas this option is only temporary solution and not permanently solve the issue.
In such an enclosed environment, total hardness will decrease when you shift pH to acidic range. pH down products can also be used to control total hardness but again, this is temporary solution.