Kh/gh Tests

[ellena]

Just bought one today and done the tests, but I'm having trouble interpreting the table at the end.
I used 5 drops of KH and 17 drops of GH.
Degrees of KH seem to = no. of drops, so that would be 5. For ppm KH/GH, I'm off the chart.
Are the 2 things supposed to go together? 5 degrees=89.5ppm etc on the chart?
Which side am I reading and why did I have to do 2 tests?
Thanks for any help!

 

[rdd1952]

You don't need to convert degrees into ppm. If you know that the KH is 5 (soft) and the GH is 17 (somewhat hard), that tells you what you need. You don't have a lot of buffering capacity (KH) but still more than I do as mine is 0-1. It's a little odd to have one high and one low as they generally run together. If on'es high, both are and if one's low, they both are. Same generally goes with pH and high pH usually comes with high GH & KH and the other way too. Below is a link that explains it pretty well.

http/www.chelonia.org/Articles/waterchemistry.htm

 

[ellena]

Thanks for the reply although I may now be even more confused
So from that link, my dH of 5 should be 70-140ppm, but it's off the scale which finishes at 215ppm.
More importantly, what does this mean for my future fish stocking choices?

 

[ellena]

Just thought-I did these tests on tap water-should I test tank water too? In fishless cycle with just 2 live plants and sand.

 

[rdd1952]

I guess I'm a little confused. How are you reading the ppm? Is there a chart or something with the kit you have? I use the API kits and you just read your level in degrees based on the number of drops it takes before the water changes to the new color (can't remember what those are at the moment). One thing I didn't see in your first post was the comment about 2 tests. Is that a test for GH and one for KH or one for degrees and another for ppm? I'm sure they exist, but I've never seen one for ppm, only degrees.

Things will sometimes bounce all over during a fishless cycle. I don't know that the GH or KH would be effected as they aren't easily changed but pH certainly is.

 

[ellena]

Yes it's the API test kit. There are 2 bottles, one for KH and one for GH. For KH, you have to add drops until it turns from blue to yellow. For GH it's from orange to green.
Then you check against the chart

It's as though they're expecting the no. of drops to be the same for both tests, which seems to make it a bit pointless having 2 tests?

 

[Rediahs]

From what I understand, KH and GH are different measures and you don't add them together or anything. You measure each against the chart. So you could have 6 degrees of KH hardness and 11 degrees of GH hardness, for example. They just happen to use the same scale.

 

[rdd1952]

They are different measures. KH is Carbonate Hardness which is the buffering capacity of your water. Buffering is what keeps the pH stable. A very low KH will mean that non-inert items in the tank would have a greater effect on the pH For instance, if you have a KH of 1 to 4, adding driftwood to the tank could lower the pH. With a KH of 15, the wood would most likely have no effect on pH.

GH is General Hardness and is basically a measure of the magnesium and calcium ions in the water. It is what people are referring to when they mention the "hardness" of the water.

In the whole scheme of things, the actual reading of GH and KH (even pH) of your water isn't terribly important. It just helps to know what they are so that you can anticipate what may happen with your tanks and to choose the fish you are going to keep. If the KH is low, then you should expect to see the pH of your water drop from the tap as nitrate, the end result of the cycling process is acidic and will lower pH. If your KH is low, then you might want to keep fish that prefer slightly acidic water unless you want to buffer the water up.

If you're KH is high, then it will be extremely difficult to lower the pH. For instance, if your pH from the tap is 7.8 and your KH is 25, then lowering the pH to keep fish such as discus that prefer something in the low 6s to upper 5s would be all but impossible without using RO water or chemicals.

And as a general rule, the three run together. Water with a high pH usually has a high GH & KH. Same goes for the low side. That's certainly not always the case as your water shows with a relatively low KH and higher GH.

 

[ellena]

Right-so I have a KH of 5 which means I have the slight acidity lots of popular tropical fish enjoy, but a GH of off the scale, so not what you'd call soft Good job I'm not looking at keeping anything especially demanding!
Thanks for explaining

 

[OldMan47]

You have a high GH of over 12 degrees which is hard water but you have a low buffering capacity of the water at only 5 degrees. This means that the mineral content of the water is fairly high with poor buffering capacity. It is a bit unusual but of course is not unheard of. All it means is that the salts dissolved in your water are not the ones that we usually find in harder water.

 

[waterdrop]

Agree with OM47. We were just having a similar discussion elsewhere I believe and its unusual to see a real-life example right around the same time. Unusual but not impossible.

-wd-