Guest bigjoe001it Posted December 16, 2003 Share Posted December 16, 2003 id like to know what the difference is between general hardness and carbonate hardness......anyone know? Link to comment Share on other sites More sharing options...
anchar Posted December 16, 2003 Share Posted December 16, 2003 Hi, Simply put GH is the amount of calcium (Ca++) and magnesium (Mg++) ion concentrationsthat are dissolved in the water. The concentartion of these ions (and others) is dependent upon the source of the water. Hard water (>200ppm) is high in Ca and Mg, whilst water (50-100ppm) is said to be soft.KH is the measure of carbonate (C03-) and bicarbonate (HCO3-) ions dissolved in water. Carbonate harness (also referred to as alkalinity) helps to satbilize the pH in the aquarium. An aquarium with a low KH (say 50ppm or less) will tend to be acidic. If the KH is very low, the water is subject to rapid pH shifts (so monitor it carefully).HTH merjo Link to comment Share on other sites More sharing options...
CThompson Posted December 16, 2003 Share Posted December 16, 2003 My rule of thumb is simpler than that (all my poor brain can handle I'm afraid)GH = where your pH isKH = how likely it is to stay there A high KH means your pH is likley to be stable, which is a good thing regardles as to the pH you want (African or American water).The GH is dependant on what fish you keep, ie. Africans = high pH, Americans = low to middle ph (6 and below).Craig Link to comment Share on other sites More sharing options...
greshaki Posted December 16, 2003 Share Posted December 16, 2003 Thanks merjo!On the same subject, is it important to test for carbonate hardness in a Malawi/tang tank, or just test General hardness and PH? Link to comment Share on other sites More sharing options...
Brett4Perth Posted December 16, 2003 Share Posted December 16, 2003 Hi Craig,I think you will find that GH is NOT directly related to pH. greshaki,You are measuring something different with carbonate hardness. :rolleyes: CheersBrett Link to comment Share on other sites More sharing options...
fishly Posted December 16, 2003 Share Posted December 16, 2003 Hi Craig,I think KH is the one related to PH :D . Correct me if I am wrong. :rolleyes: Link to comment Share on other sites More sharing options...
CThompson Posted December 16, 2003 Share Posted December 16, 2003 How about if I stick withGH = where your pH isKH = how likely it is to stay there Do people agree with this ?Craig Link to comment Share on other sites More sharing options...
Willy Wombat Posted December 16, 2003 Share Posted December 16, 2003 Craig - I dont agree GH refers to something not directly related to pH. It refers to the level of calcium and magnesium ions dissolved in the water. The more ions dissolved - the harder (GH) the water. Just to confuse you, ions of the the element "iron" can also have a limited effect on the hardness of the water. :rolleyes: CheersWW Link to comment Share on other sites More sharing options...
CThompson Posted December 16, 2003 Share Posted December 16, 2003 The more ions dissolved - the harder (GH) the water. Isn't harder water normally alkaline?I add Epsom salts to my water change barrels for the GH (to get the pH up there), and I add carbonate hardness generator (KH?) to stabilise the pH.Is my understanding/usage incorrect? Or am I talking at cross-purposes?Craig Link to comment Share on other sites More sharing options...
Willy Wombat Posted December 16, 2003 Share Posted December 16, 2003 Hi craig - Epsom salts are generally derived from magnesium sulfate. Depending on how they are manufactured - they can contain other elements, but the vast majority of epsom salts will be magnesium sulfate. So when you are adding epsom salts - they will add a lot of magnesium ions into your water - making it "hard". This will also effect the Ph - as you are adding sulfate to your tank. Sufate ions will bring about a small shift down in ph (acidic) so i doubt that the substance you are adding to your water is "just epsom salts", if it is making the pH rise. It probably has some other stuff mixed in with it. The addition of sodium bicarbonate (baking soda), to the water will increase both your pH and the buffering capacity (KH) of the water. Calcium carbonate (eg oyster shells, calcite rocks) will have the added bonus of increasing carbonate hardness and Calcium ion concerntration (GH) . Link to comment Share on other sites More sharing options...
Jim Posted December 17, 2003 Share Posted December 17, 2003 I agree with WW, the way i always remember it is,GH = Salts - magnesium and calcium in the waterKH = Buffers - measurement of carbonates in the water,keeps ph stable Link to comment Share on other sites More sharing options...
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