Kh & Gh

[Luke_e]

Tested my GH and KH (from tap water), and i got 17.9ppm for each. Is this good or bad? Once i get my gravel i'm going to use a DIY nutrafin kit for co2.

 

[alanchown]

Tested my GH and KH (from tap water), and i got 17.9ppm for each. Is this good or bad? Once i get my gravel i'm going to use a DIY nutrafin kit for co2.

Are you sure about the units? My tap water is about 180ppm Kh, which equates to about 11 degrees.

Alan

 

[craynerd]

achown, living in london you will have much higher readings.

Luckily i`m up north and i see Luke is as well. my tap is:

pH=6.8 ppm
KH=25 ppm
GH=40 ppm

I suspect they are correct at ppm.

Chris

on closer inspection tho: what test kit are u using to read to decimal of 0.1 ? My test kit reads to the nearest 10 ppm

 

[alanchown]

achown, living in london you will have much higher readings.

Luckily i`m up north and i see Luke is as well. my tap is:

pH=6.8 ppm
KH=25 ppm
GH=40 ppm

I suspect they are correct at ppm.

Chris

on closer inspection tho: what test kit are u using to read to decimal of 0.1 ? My test kit reads to the nearest 10 ppm

As you say London tap water can almost be sliced! www.yorkshirewater.com gives you very comprehensive details of water quality-just enter the postcode on the homepage. The average for the area is a GH of 21 ppm, which I would have thought was nice and soft.

Alan

 

[craynerd]

Good find! I`ll have to see if Lancs has one.

Well an average of 21ppm isnt too far of what he wrote at 17.9ppm

although i`m confused where the hell the 0.9 is ! or even the 7 for that matter ! lol

 

[alanchown]

Good find! I`ll have to see if Lancs has one.

Well an average of 21ppm isnt too far of what he wrote at 17.9ppm

although i`m confused where the hell the 0.9 is ! or even the 7 for that matter ! lol

My water Authority (Essexand Suffolk) doesn't seem to provide the same details- it just lists the standards, and how many samples failed.
Standards seem to be Nitrates <50ppm, Nitrites 0.1 ppm, PH 6-10 (although 7.5-8 seems to be what they aim for). Phosphorous (=phosphates??) No standard.

Alan

 

[Luke_e]

Thanks for the replies everyone.
My test kit is an API Liquid GH & KH Test Kit, and it says after adding 1 drop of the test solution (for both) if it turns to X colour after 1 drop it = 17.9ppm. If it takes more you look at the chart and that gives you your ppm..
So, in terms of a planted tank, with a DIY co2 injection, and 2wpg (its 70l tank with 30w of light) is 17.9ppm for KH and GH a good or bad thing?

 

[craynerd]

KH is the buffering capacity. Do a search on it, basically its like a spunge for free hydrogen ions.

It allows the pH to maintain stable as acids are added. CO2 produces carbonic acid, so when u start to add it your pH will drop!

With regards to if your KH is ok, i don`t think it matters! People are under the impretion that a low KH means a larger pH swing but this isn`t the case.

I got this from another site and saved it: sorry i forgot where its from.

Myth: A Low KH results in a larger pH swing when adding CO2.
Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.
Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

Hope that helps

 

[Luke_e]

Thats helped Cray, much appreciated mate.

 

[Gnatfish]

Myth: A Low KH results in a larger pH swing when adding CO2.
Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.
Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

That looks like its from here

 

[craynerd]

There u go!! Quality site and some great articles! V interesting!

Chris

 

[George Farmer]

Tested my GH and KH (from tap water), and i got 17.9ppm for each. Is this good or bad? Once i get my gravel i'm going to use a DIY nutrafin kit for co2.

I would personally build your KH up to 3 degrees and GH up to 5 degrees. This should provide you with enough KH to provide adequate buffering for CO2 injection and enough GH to provide sufficient levels of calcium (Ca) and magnesium (Mg) so your plants don't suffer from deficiencies.

To boost KH add baking soda (not bi-carbonate of soda). 1 teaspoon per 100 l. boosts by 1 dKH.
To boost GH add a 4:1 ratio of Calcium chloride (CaCl2) and Magnesium sulphate (MgSO4 or Epsom salts). For quantities do a google as I have no experience of this.

Or buy Kent KH stable to boost KH and Seachem Equilibrium to boost GH.

I'm not sure what gravel you are buying. Plain pea gravel often contains lime that will also boost pH and hardness - not a good thing as you have no control so try and use an inert substrate i.e. quartz gravel or silica sand. Aim for a grain size of 1-3mm and mix with a nutrient-rich additive or tablets for best results.

 

[Luke_e]

Thanks for the reply gf225..

To boost the KH and GH do i add the baking soda to the aquarium water, and would i need to top it up after water changes?

Where can i get hold of calcium chloride?

If i bought the Kent stuff, would this need to be topped up after a water change?

See my tank diary to see what gravel i got, it wasnt a brand of gravel, simply labled as 'aquarium gravel' at my LFS..

Cheers .

 

[George Farmer]

I would adjust the tank water to the required hardness. Then with every water change adjust the new water prior to adding to the tank thus keeping a stable hardness.

If you can't get hold of Calcium chloride then you can use Calcium sulphate - http/www.aquaessentials.co.uk/index.php?...x&cPath=145_146

 

[Luke_e]

Thanks mate, much appreciated.