Question on GH and KH

[Emg]

I'm not that familiar with gh and kh and what exactly that means...something about the total disolved salts in the water....and the "buffering" ability or alkalinity of the water.......

But what does that all mean for my plants and fish ? I just measured the water coming out of my tap and the readings I get are.......

PH-7.8
GH-40ppm
KH-60 mg/l

OK, I see I have very soft water, but my PH runs a bit on the high side. The instructions with the test kit say that a low GH reading generally means your PH is on the lower side........my water isn't cooperating with the general rule......why could that be ?

I guess my question is.......what do these readings mean as far as my plants go....(not worried about the fish, they're all doing fine) I read that one of the readings has something to do with the plants ability to use CO2........am I ok in that area with these readings ?

Thanks for any info !

 

[phanmc]

pH: the acidity/alkaline levels of water
gH: total dissolved concentration of calcium and magnesium
kH: total dissolved concentration carbonate and bicaorbonate, which acts as buffer against acidity.

gH is not tied directly to pH, its just waters that are usually low in gH tend to be low in pH as well.

While there are a few plants that are sensitive to gH levels, most plants will adapt to the gH so you can pretty much ignore it.

Your kH level, when compared to your pH level, shows that you have very little CO2 in your tank (1.6ppm). Your plants would benefit from a little CO2 injection. For more on calculating CO2 levels, check out Chuck Gadd's site

 

[Emg]

Thanks Phan......Just the sort of info I was looking for.

Those numbers were what I got directly from my tap water. I dose with Florish Excel in my planted tanks......should I do a reading on those tanks as well ? If there's enough carbon in the water from the excel dosing, will that show up in the KH reading ?? Or..will I have to get a carbon test kit to check that out ?

Thanks for the article Phan.....I read through it...very slowly...lol....I'm having a hard time putting all those pieces together.....thanks for helping out !

 

[phanmc]

The kH/pH table only measure CO2 because CO2 is acidic, while the carbon in Flourish is not so it won't show up in the kH/pH table. If you're using Flourish then you probably don't need to worry about injecting CO2, though it will still benefit them to have a constant supply of carbon during the day.

 

[Emg]

Thanks Phan !