Water chemisty.

[suphew]

Arn't they the same thing? From the links above

Carbonate hardness, or Carbonate alkalinity is a measure of the alkalinity of water caused by the presence of carbonate (CO32-) and bicarbonate (HCO3-) ions.

An aqueous solution containing 120 mg NaHCO3 (baking soda) per litre of water will contain 1.4285 mmol/L of bicarbonate......

[alanmin4304]

Soap is sodium stearate and the stearate locks up with the calcium and magnesium ion to form an insoluble scum in your bath. The soap will not work until all the calcium and magnesium ions are used up and this is a measure of the hardness of the water. The original test for water hardness was a titration against a known solution of soap---it will not froth until the hardness has been locked up. Detergents work regardless of the hardness because one end of the molecule is soluble in water and the other in water. Bicarbonate and carbonate alkalinity has nothing to do with the hardness itself. You can make the water harder by adding any soluble calcium or magnesium salt such as calcium chloride.

[Jennifer]

The bicarbonate + metal cations produces 'carbonate hardness' (aka temporary hardness). Free bivalent metal ions produce 'general hardness.'

The process of carbonate hardness is an equilibrium equation and in a tank with an average temperature the level of aqueous CO2 will be relatively constant so there will be aqueous free ions as well as precipitating solid calcium carbonate. Removing CO2 (e.g. by heating) will push the equastion in one direction while a lack of bicarbonate will push it in the opposite direction.

Ca2+(aq) + 2HCO3-(aq) CaCO3(s) + CO2(aq) + H2O

There will be a test on this tomorrow. :lol:

[alanmin4304]

Who will be marking the test? Watch my lips. Hardness is a measure of the calcium and magnesium ions in the solution. Carbonate and bicarbonate stabilise the reaction and act as a buffer. Bicarbonate stops more cations from forming an insoluble carbonate and taking the calcium ions out of solution and therefore decreasing the hardness (or availability of Ca++) hence two seperate terms--KH & DH. Mrs google does not sit on the right hand side of god--her husband does. Have a good day ya all.

[Jennifer]

Don't give away all the answers Alan! The test will be closed-book, no Google either. Study up on your acid base chemistry and your carbonate solubilities people!

[suphew]

I'm not a chemist so what are saying may well be true Alan, but in the real world of actually testing our water, calcium tests measure the calcium levels, magnesium tests measure the magnesium levels, and KH/Alk tests measure the Carbonate hardness. I have all three Salifert test kits sitting in front of me now and it's spelled out pretty clearly on the boxes.

http://www.marinedepot.com/Salifert_KH_Alkalinity_Test_Kit_Alkalinity_(KH)_Test_Kits_for_Saltwater_Aquariums-Salifert-SF1123-FITKAL-vi.html

•The total carbonate and bicarbonate concentration is also called alkalinity or carbonate hardness and for...

I'm constantly monitoring and adjusting the levels of all 3 (ca mg and Kh) in my marine tank, and watch my lip's, I can have very high levels of Calcium and Magnesium and very low levels of hardness, similarly I can have very high Alk/hardness levels and low ca/mg levels. The 3 are of course very closely related and levels do affect each other BUT they are different things.

[suphew]

http://fins.actwin.com/aquatic-plants/month.9506/msg00121.html

The "KH" test kit measures the total alkalinity, of which "carbonate

hardness" (KH) is a major contributor. KH is the measure of

bicarbonate (HCO3-) and carbonate (CO3--) ions in the water.

GH is general hardness and is the measure of primarily calcium (Ca++)

and magnesium (Mg++) ions in the water.

The posters question was how to raise their Kh to the correct levels for their cichlids

4) What can I do in the mean time to raise my pH and KH?

Try adding some baking soda (sodium bicarbonate). It will raise your

KH and pH.

[alanmin4304]

I was discussing the very first post.

[alanmin4304]

just to show that I don't hate Mrs Google, here is part of an article. I have edited it a bit because it was about turtles but the science is the same for fish. I understand that the term "water hardness" originates from how hard it is to get get soap to lather. The more calcium or magnesium ions present the "harder" it is to get the soap to lather.

Return to World Chelonian Trust Main Page for more Turtle and Tortoise Information

Water Chemistry: pH, GH and KH What are they all? - Scott Thomson

Copyright © 2003 World Chelonian Trust. All rights reserved

Related articles:

Understanding Biological Filtration - Jody Karlin

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Introduction :

The water chemistry requirements for turtles are often underestimated. At the same time it needs to be acknowledged that they are not fish and hence are not susceptible to going belly up from a rapid pH change.

Some species do benefit from a more exacting regime, and it can be said that there are health benefits, even if indirect, from careful monitoring and adjustment of these water quality parameters.

First of all I will define these terms as I think we all probably have some knowledge of what pH means but some detailed knowledge is required.

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Per Hydrogen (pH)

The pH of the water is a measure of the balance between the Hydrogen (H+) and Hydroxide (OH) ions in the water. I think most of us know that low pH is acidic and high pH is alkaline or basic. Hence a pH of 5 is slightly acidic water, a pH of 7 is neutral and a pH of 8 is alkaline water.

For the budding chemists the equation is as follows:

pH = -log10[H3O+]

All right enough of the chemistry but there is an important point here and any mathematicians will see it. The pH scale is a logarithmic scale. In other words a pH of 6.0 is 10 times more acidic than a pH of 7.0 and a pH of 5.0 is 100 times more acidic than a pH of 7.0. As a keeper you need to be aware that it is not a difference of 1 when you go from 6.0 to 7.0.

Ways to lower pH

Filtering water over peat

Add bogwood to the tank

Inject carbon dioxide CO2

Use a commercial acid buffer

Water changes with softened water or RO (Reverse Osmosis) water

Ways to raise the pH

Aerate the water, driving off the carbon dioxide (CO2)

Filter over coral or limestone

Add rocks containing limestone to the tank or use a coral sand substrate

Use a commercial alkaline buffer

Carbonate Hardness (KH)

This is an area where many people get confused. One of the reasons the term alkaline is avoided a bit and the term Basic is used for the pH scale is because this reading is measuring the alkalinity of the water. It is not the same as alkaline.

The alkalinity is a measurement of the waters buffering ability, or its ability to absorb and neutralise acid. Clearly the more alkalinity or the higher the Carbonate Hardness of the water the less likely you will incur pH swings in the water. It is therefore important to get this figure reasonably high to stabilise the water.

Exactly how high you want your dKH (degrees of KH) will depend on what pH you choose to use. To people keeping fish from the African Lakes this is the life and death of their fish. Those fish live in very stable high pH conditions, they do not like change and the conditions can be difficult to imitate. Fortunately turtles are not quite so sensitive. However, I do think that basic fish keeping can teach the aquatic turtle keeper a thing or two about water.

Ways to increase kH

Adding sodium bicarbonate (baking soda). One teaspoon of baking soda added to 50 liters of water can raise the kH of the water by approx 4 deg dH without a major affect on pH.

Adding an air stone to increase surface turbulence driving off carbon dioxide (CO2)

Adding commercially available products to increase buffering capacity

Ways to lower kH

Injecting carbon dioxide (CO2)

Use reverse osmosis (RO) water. You can mix tap water with reverse osmosis water to achieve the desired kH.

Adding commercially available products to decrease the buffering capacity.

Do not use distilled water as it has no dissolved salts and hence no buffering ability. Add a small amount of acid (eg uric acid) and it will shift the pH very rapidly. It is also highly osmotic and will react with the turtles renal system.

General Hardness (GH)

This is essentially a measurement of Magnesium and Calcium ions in the water. Again it is measured in the German degrees of hardness scale or parts per million. This is what is generally meant by soft and hard water which are terms people should be familiar with. The table below shows comparisons between parts per million, the dH scale and the generalised concepts of soft and hard water.

Ways to increase gH

Adding limestone to the aquarium (this will also increase kH which in turn will increase pH)

Adding calcium carbonate will raise gH and kH

Ways to reduce gH

Adding peat moss to your filter

Use commercially available water softening pillows or a water softener (this removes calcium and magnesium ions and replaces them with sodium ions. Many people feels that this is an unacceptable method of softening water as many fish that prefer soft water don’t like sodium either.

Mixing tap water with reverse osmosis (RO) water.

General Hardness Table

0 to 4 dH 0 to 70 ppm Very Soft

4 to 8 dH 70 to 140 ppm Soft

8 to 12 dH 140 to 210 ppm Medium Hard

12 to 18 dH 210 to 320 ppm Fairly Hard

18 to 30 dH 320 to 530 ppm Hard

[Caryl]

Please Sir, my brain is full!