Degrees German

[j4the96]

Hi

Are Degrees German the same as GH ? I have tested my water using the Sera GH test and it takes 9 drops to change colour so i assume thats 9dGH.

My water providers website says 4.98 degrees german

If Degrees German is the same as GH why the difference

cheers guys

 

[Alastair]

Hi

Are Degrees German the same as GH ? I have tested my water using the Sera GH test and it takes 9 drops to change colour so i assume thats 9dGH.

My water providers website says 4.98 degrees german

If Degrees German is the same as GH why the difference

cheers guys

Hi, yes General hardness is measured in German degrees and when measuring carbonate hardness (Kh) this is also expressed in German degrees (dkh)
There isn't any difference as far as I'm aware




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[Ravenswing]

GH=Gesamt Härte, KH=Karbonat Härte, unit of measure is dH=deutsche Härte with both GH and KH. Hardeness= GH, alkalinity=KH

 

[dw1305]

Hi all,

GH=Gesamt Härte, KH=Karbonat Härte, unit of measure is dH=deutsche Härte with both GH and KH. Hardeness= GH, alkalinity=KH

It is like "Ravenswing" says you need to know whether you are looking at carbonate (or temporary) hardness (dKH) or general (or permanent) hardness (dGH).

We often use the terms interchangeably because most of the hardness and alkalinity in our water comes for calcium carbonate (CaCO3), which supplies both, and that often both measures are expressed in terms of their calcium hardness, even if another divalent cation (Mg++) was involved.

Have a look at these 2 threads: <How Do I Work Out K/Mg/Ca in Tap Water? | UK Aquatic Plant Society> & <How Do I Work Out K/Mg/Ca in Tap Water? | UK Aquatic Plant Society>, JamesC is excellent, although the best explanation for the more chemically minded is probably still this one at "the Krib" <Water Hardness>
Their derivation is a bit strange, because you have to use CaO in the calculation, specifically,

1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of water, which is equivalent to 0.17832 mmol per litre of elemental calcium and/or magnesium ions, since CaO has a molar mass of 56.0778 g/mol. In water testing, paper strips often measure hardness in parts per million (ppm), where one part per million is defined as one milligram of calcium carbonate (CaCO3) per litre of water. Consequently, 1 dGH corresponds to 17.848 ppm, since CaCO3 has a molar mass of 100.0875 g/mol.

and

One German degree of carbonate hardness (dKH) corresponds to the carbonate and bicarbonate ions found in a solution of approximately 17.848 milligrams of calcium carbonate (CaCO3) per litre of water (17.848 ppm). Both measurements (mg/L or KH) are usually expressed "as CaCO3" – meaning the concentration of carbonate expressed as if calcium carbonate were the sole source of carbonate ions. Bicarbonate ions only contribute half as much carbonate hardness as carbonate ions, so bicarbonates that are present in the water are converted to an equivalent concentration of carbonates when determining KH.

cheers Darrel

 

[j4the96]

Thanks for the replies

This is the information on the water company's website



Avg Hardness Hardness Classification Degrees Clark Degrees German
89 35.6 moderately soft 6.23 4.98


Anyone any idea what my GH is ?

Thanks

 

[j4the96]

Well that didn't copy and paste the way I thought it would.

It's basically saying

Degrees Clark 6.23
Degrees German 4.98

Thanks again

 

[ceg4048]

Hi,
You need to stop worrying about this. You specifically stated in your OP that you measure the GH at 9. The water report is only a sampling of measurements taken at various location in your municipal zone. It does not provide measurements for every house on every block. So just carry on and forget about anything else. There are at least a half dozen ways to measure GH, just like there are plenty of ways to measure weight (grams or ounces) or distance (feet or meters). The test kits report in German degrees. It doesn't really matter if your measurements don't coincide with the report. Stop complicating your life.

Cheers,

 

[j4the96]

Thanks for your reply. My problem is I don't know which EI starter kit to get from TNC. The soft water one or the hard water one. I also have CRS in my tank and don't really want to add any more magnesium but then again don't want my plants to suffer

Cheers

 

[dw1305]

Hi all,

You need to stop worrying about this.

Ditto

It's basically saying Degrees Clark 6.23 Degrees German 4.98

Same measurement, just different units. 1 dGH is approx 1.25 Clark <Hard water - Wikipedia, the free encyclopedia>, so ~5dGH and ~6.25 Clark.

My problem is I don't know which EI starter kit to get from TNC. The soft water one or the hard water one. I also have CRS in my tank and don't really want to add any more magnesium but then again don't want my plants to suffer

If you live in the UK there is unlikely to be much magnesium (Mg) in your tap water. If you have RCS Red Cherry Shrimp, it won't bother them either way. If they are CRS Crystal Red Shrimp, I haven't kept them, but they would probably be better without EI. Have a look at "Ady34's" Nano thread: <Aquanano40 CRShrimp tank....little video | UK Aquatic Plant Society>

cheers Darel