Understanding some water chemistry (pH, kH, gH)

Here is an extract taken out from the instruction kit of Aquarium Pharmaceuticals. http://www.aquariumpharm.com/testkits/gh-kh.html

What is Carbonate Hardness (KH)?
Carbonate hardness (also known as alkalinity) is the measure of carbonate (CO32-) and bicarbonate (HCO3-) ion concentrations dissolved in water. These minerals are present in municipal, well, and bottled spring water. The level of carbonate hardness in tap and bottled water depends on the source of the water and the treatment processes it has undergone.

Carbonate hardness helps stabilize pH in the aquarium. An aquarium with a low KH level (50 ppm or less) will tend to be acidic. Aquariums with very low KH are subject to rapid pH shifts, if not monitored carefully. Water with a high KH level (= 200 ppm) usually has a high pH. The Aquarium Pharmaceuticals KH (Carbonate Hardness) Test measures KH in German degrees (°dKH). To convert °dKH to parts per million (ppm), multiply °dKH x 17.9.

What is General Hardness (GH)?
General hardness is the measure of calcium (Ca2+) and magnesium (Mg2+) ion concentrations dissolved in water. These minerals are present in municipal, well, and bottled spring water. The level of general hardness in tap and bottled water depends on the source of the water and the treatment processes it has undergone. Hard water (= 200 ppm) is high in calcium and magnesium, while soft water (50 to 100 ppm) is low in these minerals. The Aquarium Pharmaceuticals GH (General Hardness) Test measures GH in German degrees (°dGH). To convert °dGH to parts per million (ppm), multiply °dGH x 17.9.


GH and KH in the Aquarium
Aquarists seek to provide a healthy aquarium environment by duplicating the water conditions of the natural habitats of their fish. Tap water rarely provides the water conditions necessary to maintain an optimal aquarium. Some tap water supplies have a very low KH level (below 3 °dKH). This type of water has very little pH buffering capacity and can contribute to wide pH swings in the aquarium. When water evaporates from the aquarium, it leaves behind hardness ions. Topping off with tap water simply adds more minerals to the aquarium, resulting in a steady increase in GH. It is therefore necessary to test the GH and KH frequently to monitor water quality and prevent stressful conditions from occurring. Use the table below to create the ideal water hardness levels for your aquarium fish. When keeping a community aquarium with a variety of tropical fish, adjust the GH and KH to 3° - 6° (50 - 100 ppm).


GH & KH RANGE - AQUARIUM LIFE
0°-3° (0-50 ppm) discus, arowanas, elephantnose, neons, cardinals, live plants

3°-6° (50-100 ppm) Most tropical fish including angelfish, cichlids, tetras, botia, live plants

6°-11° (100-200 ppm) Most tropical fish including swordtails, guppies, mollies, goldfish

11°-22° (200-400 ppm) Rift lake cichlids, goldfish, brackish water fish

[jwhtan]

perhaps a little write-up or contribution on the water chemistry in particular relation to the Aquascaping aspect will be good

hum... talking about PH, KH & GH. i would like to share with you all with this too.

this link give very good info about how to lower / increase PH , KH & GH
http://www.drhelm.com/aquarium/chemistry.html

Originally Posted by andrewtyr

Here is an extract taken out from the instruction kit of Aquarium Pharmaceuticals. http://www.aquariumpharm.com/testkits/gh-kh.html

What is Carbonate Hardness (KH)?
Carbonate hardness (also known as alkalinity) is the measure of carbonate (CO32-) and bicarbonate (HCO3-) ion concentrations dissolved in water. These minerals are present in municipal, well, and bottled spring water. The level of carbonate hardness in tap and bottled water depends on the source of the water and the treatment processes it has undergone.

Carbonate hardness helps stabilize pH in the aquarium. An aquarium with a low KH level (50 ppm or less) will tend to be acidic. Aquariums with very low KH are subject to rapid pH shifts, if not monitored carefully. Water with a high KH level (= 200 ppm) usually has a high pH. The Aquarium Pharmaceuticals KH (Carbonate Hardness) Test measures KH in German degrees (°dKH). To convert °dKH to parts per million (ppm), multiply °dKH x 17.9.

What is General Hardness (GH)?
General hardness is the measure of calcium (Ca2+) and magnesium (Mg2+) ion concentrations dissolved in water. These minerals are present in municipal, well, and bottled spring water. The level of general hardness in tap and bottled water depends on the source of the water and the treatment processes it has undergone. Hard water (= 200 ppm) is high in calcium and magnesium, while soft water (50 to 100 ppm) is low in these minerals. The Aquarium Pharmaceuticals GH (General Hardness) Test measures GH in German degrees (°dGH). To convert °dGH to parts per million (ppm), multiply °dGH x 17.9.


GH and KH in the Aquarium
Aquarists seek to provide a healthy aquarium environment by duplicating the water conditions of the natural habitats of their fish. Tap water rarely provides the water conditions necessary to maintain an optimal aquarium. Some tap water supplies have a very low KH level (below 3 °dKH). This type of water has very little pH buffering capacity and can contribute to wide pH swings in the aquarium. When water evaporates from the aquarium, it leaves behind hardness ions. Topping off with tap water simply adds more minerals to the aquarium, resulting in a steady increase in GH. It is therefore necessary to test the GH and KH frequently to monitor water quality and prevent stressful conditions from occurring. Use the table below to create the ideal water hardness levels for your aquarium fish. When keeping a community aquarium with a variety of tropical fish, adjust the GH and KH to 3° - 6° (50 - 100 ppm).


GH & KH RANGE - AQUARIUM LIFE
0°-3° (0-50 ppm) discus, arowanas, elephantnose, neons, cardinals, live plants

3°-6° (50-100 ppm) Most tropical fish including angelfish, cichlids, tetras, botia, live plants

6°-11° (100-200 ppm) Most tropical fish including swordtails, guppies, mollies, goldfish

11°-22° (200-400 ppm) Rift lake cichlids, goldfish, brackish water fish

hi bro, how to reduce my kH (6 to 8).. im keeping tetra...