# Is water PH and hardness the same?



## stuckinthemiddle (Feb 26, 2008)

Question for everyone, is water PH and hardness the same? If not, whats the difference?

thanks!


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## Adrnalnrsh (Mar 18, 2008)

No, hardness usually has to do with calcium and sodium I think and PH has to do with the Acidity and Alkalinity of the water.


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## crabs (Apr 17, 2008)

That is pretty much correct...

pH is the acidity, the higher the pH eg. 9 or 10 then the less acidic, the lower the pH say 3 or 4 the more acidic, a ph of 7 to 7.5 is neutral


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## aussieafricans (Dec 19, 2007)

pH=7
Alkaline=anything above 7, 7.1 being not very alkaline and 14 being Extremely alkaline
Acidity= anything below 7, 0.1 being most acidic and 6.9 being least acidic

pH= power of Hydrogen

Carbonate hardness is usually a stabilizer of the pH so the pH doesn't vary(quickly)

if anyone would like to correct me i would love for you to do so. :thumb:

Good luck hope this helps


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## naegling23 (Jan 4, 2008)

aussie, your actually pretty close

pH = inverse log of the concentration of hydrogen ions  I know that doesnt mean anything to non-chemists though. For the aquarium hobbiests, 7 is neutral, anything lower than 7 is acidic, and higher than 7 is basic (or alkaline). The further away you go from 7, the more acidic, or more basic it is, its the inverse log of the concentration, because acidic means more free hydrogen ions (the inverse part, lower numbers = higher concentration) and log because 1pH unit = a 10 times increase in the concentration.

Hardness = the amount of dissolved salts/solids in the water. When I say salts, I dont mean just table salt, I mean the chemical salt, so things like sodium chloride (table salt), calcium chloride, calcium carbonate, etc.

Hardness does not necessarily equal buffering capacity, but gives a rough indication. Some salts, like calcium carbonate do provide buffering capacity (buffering is the ability of a solution to resist large changes in pH, think of it as a sort of sponge). Other salts like sodium chloride do not provide any buffering capacity. However, the more dissolved solids you have in the water, the more likely you are to have increased buffering capacity.


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## Rick_Lindsey (Aug 26, 2002)

naegling23 said:


> Hardness does not necessarily equal buffering capacity, but gives a rough indication. Some salts, like calcium carbonate do provide buffering capacity (buffering is the ability of a solution to resist large changes in pH, think of it as a sort of sponge). Other salts like sodium chloride do not provide any buffering capacity. However, the more dissolved solids you have in the water, the more likely you are to have increased buffering capacity.


Indeed. Many aquarists distinguish two sorts of hardness, general and "carbonate" hardness (kH). General hardness is exactly what naegling23 described. "Carbonate" hardness is a good indicator of the buffering capacity. A high kH generall leads to a high pH, and also a fairly stable pH. As naegling pointed out hard water often has both a high gH and a high kH, but there are a number of salts that increase gH only, not kH.

-Rick (the armchair aquarist)


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## stuckinthemiddle (Feb 26, 2008)

Thanks everyone!

So will adding aquarium salt or non-iodized salt increase water hardness for my african tank? I currently have not been adding to increase hardness.

thanks everyone!


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## zugbug (Dec 12, 2005)

short answer no, adding salt (sodium chloride) will not increase hardness, adding Epsom salts (magnesium sulfate) will. Hardness measures calcium and magnesium in the water.

Thats why you use salt with your water softener in your house, the resin in the softener exchanges the calcium and magnesium in your hard water with sodium
(from the salt).


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## stuckinthemiddle (Feb 26, 2008)

So will sodium chloride hurt my african tank? I added Aquarium salt on my last water change thinking that it would increase hardness, but will switch to Epsom Salt. How much should I add if I do a 30% water change on my 55g.

wish I had paid more attention in my chem 101 class than to the girl sitting next to me....


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## zugbug (Dec 12, 2005)

the salt wont hurt....depending of course on how much you added. You will want some salt in your cichlid tank. How much epsom salt to add will depend on how hard your water is to begin with. Check 1st, then I would try adding 1 tsp to a 1 gallon bucket and see the change. Then do the math and add the appropriate amt to your tank


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## stuckinthemiddle (Feb 26, 2008)

Ok, thanks everyone!


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