kh

[cindy]

The way I understand kh, is its the balance for the ph. If the KH is 80 - 120, the ph is more stable if we get rain or any change. Also the kh feeds the biological filter. Kh was something I didn't use to check but after seeing how quickly a ph can crash, I check it when I check my amm, ph and nitrite.

I have a mature filter and would love to add additional space for oyster shells in the future but for right now when I do a 10% change, I check and if its low, I just add some bs. The pond and aquarium.

[l113892]

What is the KH of your tap water?
What is the KH of your pond?
What KH are you trying to achieve and why?
What type of filtration are you using- bead filters, open filters, etc.?

[koibooi]

KH is Total Alkalinity or Carbonate Hardness and is a measure of the buffering capacity of the water in the pond. The buffering capacity refers to how well the pond can resist changed in pH. As I understand, the minimum KH should not be below 4 degrees of hardness and the ideal is between 6 degrees and 8 degrees.

I must say that I do not quite understand this "buffering" business.

I have however never been successfull in actually measuring my KH. the NT Labs test kit say that you must add one drop of solution to the water sample and then the water turns pale blue. Then you must keep on adding drops until the blue turns to yellow.

When ever I did the test, my water was yellow from the start so I have never managed to actually measure KH. I do have a 2 meter long by 300 mm wide by 300 mm deep tray in my trickle tower which is filled with oyster shells so my pH is always stable.

[Drew A.]

"CARBONATE HARDNESS

Carbonate hardness (KH) is the measure of bicarbonate (HCO3-) and
carbonate (CO3--) ions in the water. In freshwater aquariums of
neutral pH, bicarbonate ions predominate and in saltwater aquariums,
carbonate ions begin to play a role. Alkalinity is the measure of the
total acid binding capacity (all the anions which can bind with free
H+) but is comprised mostly of carbonate hardness in freshwater
systems. Thus, in practical freshwater usage, the terms carbonate
hardness, acid binding, acid buffering capacity, and alkalinity are
used interchangeably. In an aquarium, KH acts as a chemical buffering
agent, helping to stabilize pH. KH is generaly referred to in degrees
hardness and is expressed in CaCO3 equivalents just like GH.

In simple terms, pH is determined by the negative log of the
concentration of free hydrogen ions (H+) in the water. If you add a
strong acid such as nitric acid to water, it completely dissociates
into hydrogen ions (H+) and its "conjugate base" or "salt", NO3- or
nitrate. The hydrogen ions freed in the reaction then increase the
concentration of hydrogen ions and reduce the pH. Since nitric acid
is the end product of the nitrogen cycle, this explains why aquarium
pH tends to decrease and nitrates tend to increase over time.

When the aquarium has some carbonate buffering in it, the
bicarbonate ions will combine with the excess hydrogen ions to form
carbonic acid (H2CO3) which then slowly breaks down into CO2 and
water. Since the excess hydrogen ions are used in the reaction, the
pH does not change very much. Over time, as the carbonate ions are
used up, the buffering capacity will drop and larger pH changes will
be noted. From this it is clear why aquariums with low KH seem
unstable - as acid is produced by biological action, the KH is used
up; when it is gone, the pH is free to drop rapidly as H+ ions are
generated."
The above is from thekrib.com

Mike S. has also written articles on this subject... I'll see if I can find the link...

[Drew A.]

http://http://www.yumekoi.com/articles/aug_2003.pdf

[farne230]

Quote: Originally Posted by koibooi KH is Total Alkalinity or Carbonate Hardness and is a measure of the buffering capacity of the water in the pond. The buffering capacity refers to how well the pond can resist changed in pH. As I understand, the minimum KH should not be below 4 degrees of hardness and the ideal is between 6 degrees and 8 degrees. I must say that I do not quite understand this "buffering" business. I have however never been successfull in actually measuring my KH. the NT Labs test kit say that you must add one drop of solution to the water sample and then the water turns pale blue. Then you must keep on adding drops until the blue turns to yellow. When ever I did the test, my water was yellow from the start so I have never managed to actually measure KH. I do have a 2 meter long by 300 mm wide by 300 mm deep tray in my trickle tower which is filled with oyster shells so my pH is always stable.

I had the same problem, went back to the pet store and replace the KH bottom twice. This was a red sea product, but this could happen to any of them. I switched brands and the kh finally worked. I am using Pharmasudicals product, but the point is the experation dates and the products have a short half life. Purchase another bottle.

[HEADACHE6]

From what I remember reading , a pH swing of .5 is not a big deal . But at what kH level would I need to be at the .5 swing (60 , 80 , 120) ? I'm lucky I guess with my kH or maybe it has something to do with proper filtering , water changes & stocking levels of koi .

I know of some mad scientist who have raised their kH up to 600+ using BS (Why I don't know , sence we all know it doesn't need to be anywhere near that level) . Hopefully they don't have a basement full of puppies & monkeys as well .

[farne230]

Quote: Originally Posted by HEADACHE6 From what I remember reading , a pH swing of .5 is not a big deal . But at what kH level would I need to be at the .5 swing (60 , 80 , 120) ? I'm lucky I guess with my kH or maybe it has something to do with proper filtering , water changes & stocking levels of koi . I know of some mad scientist who have raised their kH up to 600+ using BS (Why I don't know , sence we all know it doesn't need to be anywhere near that level) . Hopefully they don't have a basement full of puppies & monkeys as well .

I am at 109ppm kh and 196 GH, with a temp of 65deg that last time I check PH swing of .5.

[KoiCop]

Bio-conversion produces carbonic acid which is buffered (think: neutralized) by KH. Once the KH has been used up, continued production of carbonic acid will cause the pH to drop. Allowed to proceed unchecked, eventually the koi will suffer from acidosis then die, and so will the bio-bugs. Game over.

With a decent source of water, and sufficient water changes, KH will be continually replenished; therefore, there's no need for most folks to add baking soda to jack their KH through the roof.

[Erns]

Quote: Originally Posted by KoiCop Bio-conversion produces carbonic acid which is buffered (think: neutralized) by KH. Once the KH has been used up, continued production of carbonic acid will cause the pH to drop. Allowed to proceed unchecked, eventually the koi will suffer from acidosis then die, and so will the bio-bugs. Game over. With a decent source of water, and sufficient water changes, KH will be continually replenished; therefore, there's no need for most folks to add baking soda to jack their KH through the roof.

so where does having oyster shells in the system fit into this?