What Is Ment By

[SeanTrollope]

what is ment by water softness and hardness

 

[sawickib]

Hard water is any water containing an appreciable quantity of dissolved minerals. Soft water is treated water in which the only cation (positively charged ion) is sodium. So its really just stuff with in your water, and certain fish live in certain environments, which have varying water chemistry, soft water just means its low in dissolved minerals. You may notice that if you have hard water that it leaves behind drops or stains on the glass, which is just dissolved minerals not water.

 

[SeanTrollope]

ok then our water is hard

 

[the_lock_man]

If your water is hard, you have to descale your kettle frequently.

 

[TwoTankAmin]

 
General hardness (GH) refers to the dissolved concentration of magnesium and calcium ions. When fish are said to prefer ``soft'' or ``hard'' water, it is GH (not KH) that is being referred to.
 
Note: GH, KH and pH form the Bermuda's Triangle of water chemistry. Although the three properties are distinct, they all interact with each other to varying degrees, making it difficult to adjust one without impacting the other. That is one reason why beginning aquarists are advised NOT to tamper with these parameters unless absolutely necessary. As an example, ``hard'' water frequently often comes from limestone aquifers. Limestone contains calcium carbonate, which when dissolved in water increases both the GH (from calcium) and KH (from carbonate) components. Increasing the KH component also usually increases pH as well. Conceptually, the KH acts as a ``sponge'' absorbing the acid present in the water, raising the water's pH.
 
Water hardness follows the following guidelines. The unit dH means ``degree hardness'', while ppm means ``parts per million'', which is roughly equivalent to mg/L in water. 1 unit dH equals 17.8 ppm CaCO3. Most test kits give the hardness in units of CaCO3; this means the hardness is equivalent to that much CaCO3 in water but does not mean it actually came from CaCO3.

General Hardness

0 - 4 dH, 0 - 70 ppm : very soft
4 - 8 dH, 70 - 140 ppm : soft
8 - 12 dH, 140 - 210 ppm : medium hard
12 - 18 dH, 210 - 320 ppm : fairly hard
18 - 30 dH, 320 - 530 ppm : hard
higher : liquid rock (Lake Malawi and Los Angeles, CA)

  from http/fins.actwin.com/mirror/begin-chem.html