gH stands for General Hardness. This is the measure of how much dissolved minerals your water contains which is mostly calcium & magnesium but also contains other mineral ions. The other mineral ions however are not as significant and are much harder to measure. Naturally occurring water and tap water around the world have different levels of dissolved minerals in them. This all depends on what kind of minerals the water has come in contact with. For example water that comes from deep inside limestone rock caves will have a high amount of the dissolved limestone in it which makes it have a much higher gH than water from a pond in an area where there isn’t much minerals in the soil or surrounding area.
gH can be confusing when it comes to measuring because it is measured differently in different parts of the world (like how US clothing sizes differ greatly from UK clothing sizes) Its best when testing your gH to read the instructions carefully and what exactly the measurements mean for your specific test. 1 Degree according to my API test kit is 17.9 parts per million of GH. gH does not affect pH like kH does, and does not have a direct co-relation to kH either. It is very important to fish and shrimps health though so it is something that cannot be ignored.
Depending on the origins of the species and the type of water they originate from each type of fish or shrimp will have different gH requirements. For example African Chiclids need to be kept in very hard water to mimic their natural habitat. Incorrect gH can affect many different things in livestock’s health. It can affect he function of internal organs and hinder proper growth as well as affect egg fertility and hinder breeding capacity. Sometimes fish can adapt to survive in different gH levels but almost always it will stop them from breeding properly.
gH is especially important to shrimp keepers and breeders because Calcium Carbonate is vital in a shrimps molting cycle and growth. Think of the shrimps exoskeleton like our own bone structure. In order for our bone structure as well as our hair and nails to grow (big and strong) we have to make sure that we absorb enough calcium from our foods such as dairy, broccoli and other greens and certain types of fish. If we don’t get enough calcium a number of health concerns can arise such as joint pain, impaired growth, brittle nails and hair. In the extreme case people can get osteoporosis which is when calcium is so deficient that a persons bones can get miniscule holes in its structure to make them fragile, brittle, and break easily.
Shrimps however can’t expand or grow their existing exoskeletons the way our bones grow and expand in size. In order for them to grow they need to shed their existing smaller exoskeletons every so often to grow a newer and bigger one. For them to be able to do this it is very important for them to have enough calcium carbonate present in the water for them to absorb and to create a strong and healthy new shell in the molting process. If there isn’t enough they wont be able to create a strong enough shell to properly fend off diseases, infections, and stress and will eventually die. Calcium Carbonate also helps in food digestion and absobtion, and helps the immune system to fight toxins, and diseases in the body and can reduce overall stress in your shrimps.
Magnesium is the key to unlocking Calcium Carbonates potential. It is able to make Calcium absorbable in the fish and shrimps bodies. Without it they would suffer from lack of calcium. It is needed for a healthy calcium absorbtion and balance as well as healthy muscles and nervous system.
Now that you know how important gH is in your tank, and what level of gH you need according to your livestock’s needs. Here are different ways to adjust your gH level.
To increase water hardness you can; use Limestone rocks that leach hardening salts, Commerical hardening salts, or if you have access to it, simply do water change with dechlorinated harder water.
To decrease your water hardness you can simply dilute it by doing water changes with softer water such as Reverse Osmosis water, Distilled water, deionized water or rainwater. There are also specific products that reduce hardness such as peat.