Gh And Kh

[Rorie]

First off, how to understand the test results. It took 4 drops for KH to turn, and 2 for GH to turn. The chart confuses me though - has a column for 'drops' then one for 'DKH' then the third with the results i guess. Can anybody enlighten me what my results come to? I am still cycling BTW.

Then, what do the KH and GH actually measure. I am slightly confused. All i understnad is it is the stability of the PH? My PH keeps dropping really low, so i gather my results should show an unstable water?

Thanks

 

[BIG BAD BARRY]

Have a read of this. Its the best explanation that i found and the info supplied by experts on this forum like waterdrop made sense.

http/fins.actwin.com/mirror/begin-chem.html

If you click the contents button at the bottom of the page it will take you to some other useful info as well.

 

[Rorie]

Thanks for that. That's helped understand what they are, but I'm still confused with how to read my Api kit. It shows me a chart for drops and how that corresponds to the two measuring conventions. But from
What I can see that's only for gh.

The kit says it's for kh too, but I don't see how that can be seen as it is measured with different units?

 

[BIG BAD BARRY]

Here is a link to the API info page for that test kit with interesting info about evaporation which you have talked about in your other post:
You need some experts help with that on the forum.

http/www.aquariumpharm.com/Products/Product.aspx?ProductID=74


I found below link as well. Not sure whether its still correct info and i have not used that kit but in terms of instructions:
I think it means:

Carbonate Hardness (KH): Each drop you add is equal to 1 dKH or 17.9 ppm KH.


General Hardness (GH): Each drop you add is equal to 1 dGH or 17.9 ppm GH.

http/www.aquareview.net/p/516/Aquarium_Pharmaceuticals_GHKH_Test_Kit.html

Somebody who has the kit should be able to confirm or assist with this.

 

[karin]

One little note, I don't know why so can't explain it but Ph tends to jump around a lot during cycling. Mine also kept dropping too low (Below 7.0) and I did corrections with sodium bicarbonate at least 3 times to keep in the target range (for me 7.5 - 8.0). Once cycled the tank stablized with the exception of when my filter went out, threw the tank into a mini-cycle and again the Ph plummeted. Post cycle the Ph got very stable.

 

[coldcazzie]

One drop of solution means one degree, so your kh is 4 and your gh is 2. Basically Kh is a measure of the amount of calcium carbonate (I think) in your water, which acts as a buffer. The end products of the cycling process are acidic compounds, so once they've "used up" the small amount of buffer in your water your ph then drops because of the acidity. Harder water areas have more buffering capacity so the ph wot drop so readily. Gh is different compounds dissolved in the water, but that doesn't have the same effect with the ph.

Sorry for terrible explanation, but figured is better than nothing!

 

[Rorie]

Smashing! That makes a lot more sense now! Does anybody know, is there is a bad upper limit for KH? They say below 4.5 is bad as it means you could have fluctuations in PH....but what about super hi KH....obviously that means the level of PH is going to stay steady. Provided you like that level of PH, is there anything bad in having a high KH?