http://www.aquariumsite.com/freshwater/chemistry.php :
Total hardness of water (GH)
Hardness making cations Ca and Mg summing up to 80% of all cations in water. Total hardness is a measure of the total concentrations of calcium and magnesium ions in water.
C. Bicarbonate (temporary) hardness of water (KH)
Carbonate hardness is a measure of the concentration of hydrogen carbonate (HCO3-) ions in as long as there is at least one calcium or magnesium ion for each HCO3- ion in water.
Note that per definition carbonate hardness dKH can not be higher than total hardness dGH.In other words, carbonate hardness measures the total concentrations of dissolved calcium and magnesium bicarbonate salts in water. Addition of Ca(HCO3)2 raises both carbonate and total hardness whereas addition of CaSO4 raises only total hardness.
Bold on minu lisandus.
Tsiteerime vahelduseks ka Walstadi kui usaldusväärset allikat:
Alkalinity is strictly defined as milliequivalents (meq) of acid required to shift a water's pH to the alkaline side of neutral. While alkalinity could be influenced by other ions (silicates, phosphates, borates, etc), the water's bicarbonate concentration usually determines most of the alkalinity. Many water treatment plants express alkalinity as ppm CaCO3 with 1 meq H2CO3 equivalent to 50 ppm CaCO3 alkalinity. However, hobbyist test kits usually express it as KH (German degree of Carbonate Hardness). One KH is equal to 17.9 ppm of CaCO3 alkalinity.
Alkalinity's pH buffering action is based on the following equilibrium reactions for dissolved inorganic carbon (DIC):
CO2+H2O <=> H2CO3 <=> H+ + HCO3- <=> CO32- + 2 H+ (valem näeb siin kole välja, sorry).
When the CO2 or H+ levels change, most of that change is absorbed by by bicarbonate.
-- jätame vahele ---
The reaction above shows the relationship between pH and CO2. Thus, when CO2 is added to the water, such as during CO2 injection the above reaction moves the right and H+ (acid) is produced, and the pH tends to go down. (How fast the pH goes down is moderated by the water's alkalinity). Conversely, when CO2 is removed from the water, such as during photosynthesis or water-air mixing, the reaction moves to the left. As a result, H+ is consumed, and the pH tends to go up. Again, how fast the pH goes up is moderated by the water's alkalinity.
Not only does CO2 affect the pH, but pH affects the CO2 concentration. For pH determines the relative proportions of CO2, bicarbonates (HCO3-) and carbonates (CO32-). At an acidic pH of 5 and below, most of the water's DIC is CO2. At pH 6.5 water contains about equal amounts of CO2 and bicarbonate, while at pH 8.5, almost all of the CO2 has converted to bicarbonates. When the water reaches pH10, about 24% of the bicarbonates have, in turn, converted to carbonates.
Veel Walstadi tsiteerides : Water hardness is the Ca and Mg concentration, often expressed as GH or ppm calcium carbonate (CaCO3).
Niipalju siis kalade söömisest.
Otsi
Postitatud: Reede Sept 24, 2004 04:53 
... ääää .... kas sellest keemia loengust saime me siis nüüd teada, et BON'i kalad on tõenäoliselt rohkem lillelembelised kui helvestoidu/ussikeste lembelised .... 