KH and ph

[gigahertz]

I finally got around to testing the KH and GH of my tank water. What I found did not make any sense to me. I hope you guys can shed some light on this.

Readings:

GH: 10dKH, KH: 1dKH, ph: 7.0 ( with CO2 injection )

I thought to have a ph of 7 the water should have more then 1dKH.

How come I'm getting a ph7 with KH at 1dKH? :huh:

[gnatster]

pH and KH are separate measurements.

pH measures how many hydrogen ions are in the water, the more ions the lower the pH, the more acidic the water.

KH measures the amount of carbonate ions that are available to counter or buffer the water from addition of additional acids.

From Dr Helm (dot) com (dagnapit, permission levels will not all me to put in a url)


Think of buffering capacity as a big sponge, the higher the buffering, the bigger the sponge. How much buffering does your tank need? The higher the kH (the bigger the sponge), the more resistant to pH changes your water will be. A tank's kH should be high enough to prevent large pH swings over time. If your kH is below roughly 4.5 dKH, you should pay special attention to your tank's pH (e.g., testing periodically) until you get a feel for how stable the pH is.
Buffering is both good and bad. On the good side, the nitrogen cycle in our tanks produces nitric acid (nitrate). If we don’t have buffering (kH), the pH will drop over time. Sufficient buffering will keep the Ph stable. On the bad side, hard water almost always has a large buffering capacity and if the pH is to high for your fish, this large buffering capacity will make it more difficult to lower the pH.

[silane]

gigahertz, do you know the ppm of CO2 in your water?

Without knowing CO2 ppm, it is hard to see if the values are ok. I remember seeing my water PH=7.X when KH=1, so your CO2 could bring it down to PH=7, it sounds correct for me. Try to get the ppm of CO2, KH, PH and CO2 should be in an equation.

[gnatster]

There are charts to available too

Like the one found in the first post here

http://www.tropica.com/article.asp?type=aquaristic&id=417

[gigahertz]

pH and KH are separate measurements.

pH measures how many hydrogen ions are in the water, the more ions the lower the pH, the more acidic the water.

KH measures the amount of carbonate ions that are available to counter or buffer the water from addition of additional acids.

From Dr Helm (dot) com (dagnapit, permission levels will not all me to put in a url)


Yes I have read that too but I'm just having problem understanding the part about raising KH. I read that if I increase the KH by adding say Calcium Carbonate I would also raise the ph.

To me a buffer means that it will stabilize the ph at certain level and will not with the addition of acid until it exceeds the buffering capacity. Now if that is the case then by adding Calcium Carbonate should not raise the ph beyond certain point and not going up in a linear fashion.

Am I just understanding that wrong or I'm missing some information? :huh:

[gigahertz]

gigahertz, do you know the ppm of CO2 in your water?

Without knowing CO2 ppm, it is hard to see if the values are ok. I remember seeing my water PH=7.X when KH=1, so your CO2 could bring it down to PH=7, it sounds correct for me. Try to get the ppm of CO2, KH, PH and CO2 should be in an equation.


I am using a Dupla CO2 indicator. So far it shows that I have the right amount of CO2 in the water( it showing green ). BUT in the owner's manual also said that of the KH of the water is below 4dKH the indicator will not show the actual amount of CO2.

What do you use to check the CO2 level for a ppm reading?

[silane]

You can use CO2 test kits. :) It should work like, how many drop of reagent before it change color, that indicate the CO2 level.

[gigahertz]

Yeah I saw that table too. According to that table my CO2 level is next to nothing which can't be true since plants are pearling like crazy in my tank.

Should I increase my KH by adding Calcium Bicarbonate? How will that affect the ph? :huh:

[gnatster]

what do you use to check the CO2 level for a ppm reading?

There are many of the same basic chart all over the net that give CO2 for given pH/KH reading. I am to new here to be afforded the courtesy of posting a url. Point google to CO2 pH Chart for links

[gigahertz]

You can use CO2 test kits. :)

Any brand you would recommand?

[silane]

gnatster,

Chart is not applicable in this case, GHZ suspect something is wrong, you need to get 3 factors to see if they are in by reference to a chart. And not, knowing 2 factors, to get the third factors.

gigahertz,

I had used one 1 brand, other test kits of this brand do not work so well, so I am not going to say out the brand here. ;)

[gnatster]

3 factors?

All you need to know is KH and pH to determine CO2 levels.

There is a mathematical formula the charts are based on.

CO2 (in PPM) = 3 * KH * 10^(7-pH) where KH is Carbonate Hardness in degrees.

[simcb]

I am using a Dupla CO2 indicator. So far it shows that I have the right amount of CO2 in the water( it showing green ). BUT in the owner's manual also said that of the KH of the water is below 4dKH the indicator will not show the actual amount of CO2.

What do you use to check the CO2 level for a ppm reading?

Try refering to this chart:

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

[silane]

3 factors?

All you need to know is KH and pH to determine CO2 levels.

There is a mathematical formula the charts are based on.

CO2 (in PPM) = 3 * KH * 10(7-pH) where KH is Carbonate Hardness in degrees.


KH, PH and CO2 are 3 factors. GHz said his KH and PH relationship does not make sense, so by using the CO2 chart to get third value (CO2) level, it does not tell anything, I reckon. So have to know the value of CO2 by testing, and uses the 3 tested values to comfirm they fall logically in the chart.

[gigahertz]

3 factors?

All you need to know is KH and pH to determine CO2 levels.

There is a mathematical formula the charts are based on.

CO2 (in PPM) = 3 * KH * 10(7-pH) where KH is Carbonate Hardness in degrees.

I did look at the table yesterday but accoring to the table my CO2 concentration is 0.9 to 1.9 ppm. That does not sound right as I am shooting a good amount into the water.

I guess at this point my question is on adding Calcium Carbonate. How much do I add per gal. to increase the KH by one dKH and how will that affect the ph? Is there a chart somewhere for that?

Thx

[gigahertz]

KH, PH and CO2 are 3 factors. GHz said his KH and PH relationship does not make sense, so by using the CO2 chart to get third value (CO2) level, it does not tell anything, I reckon. So have to know the value of CO2 by testing, and uses the 3 tested values to comfirm they fall logically in the chart.


I see what you're getting at. I will go get a CO2 test kit at my wholesaler tomorrow. Hopefully the shrimps I order last week will be in also :D

Thanks you guys for helping me out with this CO2 thing :)

I will report back with the readings once I got the kit and performed the test.

[silane]

I did look at the table yesterday but accoring to the table my CO2 concentration is 0.9 to 1.9 ppm. That does not sound right as I am shooting a good amount into the water.

I guess at this point my question is on adding Calcium Carbonate. How much do I add per gal. to increase the KH by one dKH and how will that affect the ph? Is there a chart somewhere for that?

Thx

It is the same chart to use. But what are the level of KH, PH and CO2 you want to achieve?

[gnatster]

I guess at this point my question is on adding Calcium Carbonate. How much do I add per gal. to increase the KH by one dKH and how will that affect the ph? Is there a chart somewhere for that?

There are tons of articles ont eh CO2 KH pH relationship and how to manipulate them for your needs. At the risk of incurring mods rath, you can find a very detailed discussion on Aquatic Plant Cental in the Fert Forum, look for the sticked post, Perpetual Preservation System v.2005 New and read the pdfs found in there.

Caveats,

1. I am an Admin on APC

2. I am NOT trying to start a PPS vs any other method debate. I only offer the articles to futher the understanding of how pH, KH and Co2 relationship works.

[gigahertz]

It is the same chart to use. But what are the level of KH, PH and CO2 you want to achieve?

These are my shrimp ( CRS and Bee Shrimp ) tanks ( 2 60G tanks sharing a sump ) so I think the ideal ph would be around 7 or slightly above. The KH I'm shooting for is around 4dKH ( so I can used the stupid Dupla CO2 indicator :p ). These are going to be heavily planted.

I'm trying to strike a balance between the soft to neutal requirement of the CRS and the 7.5 ph requirement of bee shrimps. What would you suggest the perameters to be?

Hey my sis told me that the airfare to SG from HK is around HK$1,200. That's cheap! I might stop by to see you in June while I'm visiting HK.

[gigahertz]

There are tons of articles ont eh CO2 KH pH relationship and how to manipulate them for your needs. At the risk of incurring mods rath, you can find a very detailed discussion on Aquatic Plant Cental in the Fert Forum, look for the sticked post, Perpetual Preservation System v.2005 New and read the pdfs found in there.

Caveats,

1. I am an Admin on APC

2. I am NOT trying to start a PPS vs any other method debate. I only offer the articles to futher the understanding of how pH, KH and Co2 relationship works.

I'll go there and check them out. I totally appreciate your inputs :)

[silane]

These are my shrimp ( CRS and Bee Shrimp ) tanks ( 2 60G tanks sharing a sump ) so I think the ideal ph would be around 7 or slightly above. The KH I'm shooting for is around 4dKH ( so I can used the stupid Dupla CO2 indicator :p ). These are going to be heavily planted.

I'm trying to strike a balance between the soft to neutal requirement of the CRS and the 7.5 ph requirement of bee shrimps. What would you suggest the perameters to be?

CRS is known to take as low as 6.0, which is good for high maintainance planted tank. Wild bee shrimps, do better in slight alkaline.

If you want to keep shrimps in high maintance planted tank, high maintainance planted need high level CO2, this would either bring the PH down or you have to use high KH to prevent the PH from falling. Either way, they are no good for shrimps, high KH is known to have poor hatch rate for certain shrimps.

The question is, do you want a shrimp tank with plant or a planted tank with shrimps? I think this questions has to be answered before deciding what shrimps and what plant to buy.

[gigahertz]

Well right now I have very low KH and I'm injecting a decent amount of CO2 with the ph being around 7.

I can most certainly live with that and so will my shrimps I think.

The whole reason of looking into KH is just for my curiousity and education on this topic. According to what I have read so far my parameters are not making sense but with everyone's help and what's on the web I'm sure that soon I should be able to understand them better.

My goal is to have planted tanks full of shrimps.

Personally I don't think that shrimps will do well in tanks that are not that well planted unless the water is constantly changed to keep nitrate in check.

High KH is not good for shrimp? Tell me more about it. This is the first time that I have heard of it. What is considered high KH for shrimps in general ( I know it differes from species to species )?

Thx :)

[simcb]

Low Kh of 2 to maximum Kh of 4 for optimium living condition.

Hmm i think the effect high KH might have something to do with causing possible death when moulting and the successful hatching of eggs is lower.

Besides that when the co2 runs out or is turn off during lights off period. There is a possiblility of the Ph rising from 6.7-6.9 to 7.4-7.5 if not monitored closely.

I guess it applies to most sensitive shrimps like bees, tigers and Crystal.