# [Wet Thumb Forum]-How do you reduce kH



## goshawk99 (Apr 11, 2006)

This is my present tank config
Tank â FW 30 gal, 6 months old
Filter - AC300 
Lighting â 3x20W, 5000k, 11.5 hours/day
Temperature â 78F
Fish - 6 White Skirt Tetra, 5 Cardinal, 2 Cory, 2 SAE, 2 CAE
Plants - Egeria Densa, Echinodorus amazonicusa, Hygrophila angustifolia, Hygrophila Corymbosa
pH â 7.6
gH - 3dH
kH â 8dH
Algae â controlled, nothing the CAE and SAE can handle
Nitrate â 5
Nitrite â 0
Ammonium â 0
PO4 - .1mg/l
Chelated Iron â >.1mg/l
Water quality â crystal clear
CO2 injection system â DIY

Any help would be appreciated

Michael


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## goshawk99 (Apr 11, 2006)

This is my present tank config
Tank â FW 30 gal, 6 months old
Filter - AC300 
Lighting â 3x20W, 5000k, 11.5 hours/day
Temperature â 78F
Fish - 6 White Skirt Tetra, 5 Cardinal, 2 Cory, 2 SAE, 2 CAE
Plants - Egeria Densa, Echinodorus amazonicusa, Hygrophila angustifolia, Hygrophila Corymbosa
pH â 7.6
gH - 3dH
kH â 8dH
Algae â controlled, nothing the CAE and SAE can handle
Nitrate â 5
Nitrite â 0
Ammonium â 0
PO4 - .1mg/l
Chelated Iron â >.1mg/l
Water quality â crystal clear
CO2 injection system â DIY

Any help would be appreciated

Michael


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## wetmanNY (Feb 1, 2003)

Your "KH" seems quite modest, so it's hard to see why you'd want to reduce it. In "KH" the "k" is for German _kalk_ or "lime"(*but see below) --the "KH" is a measure of alkalinity, which counts the water's ability to resist the addition of acids without dropping in pH. In "KH" the alkalinity is measured _as if_ it were all carbonates, even though phosphates (and borate if you had it) play a role.

That said, the way to reduce alkalinity is through dilution (either with distilled or r/o water or rainwater) or by dissolving it with infused carbon dioxide.

* K for _karbonat_-- I should have known this...

[This message was edited by wetmanNY on Mon April 07 2003 at 09:26 PM.]


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## goshawk99 (Apr 11, 2006)

hmmmm... but if you look at the charts... kH/pH the CO2 is below the acceptable level of 11 - 24. So with that logic... lowering kH will likely lower the pH and eventually get the CO2 to be in the right range.

With that said about infusing CO2, how do you do that with a DIY, I got one 2L bottle that seems to be producing the CO2.

Michael


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## Jim Miller (Feb 3, 2003)

lowering the kh will just allow the same co2 level to produce a lower ph level. it won't increase the co2 level.

co2 concentration and kh are independent variables in this equation, ph is the dependent variable.

jtm

Tank specs in profile

[This message was edited by Jim Miller on Thu March 27 2003 at 10:29 AM.]


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## Roger Miller (Jun 19, 2004)

I agree with the previous statements that a) you don't need to decrease your KH, b) decreasing KH will not get you more CO2 and c) the best way to reduce KH is to dilute it.

For the sake of giving a complete answer, you can also reduce KH by adding a strong acid. Usually this means hydrochloric or sulfuric acid. I don't recommend that approach.


Roger Miller


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## imported_Soggy (Feb 6, 2003)

This topic has perked my attention. I have water that has 20 kH and 20 gH according to my sera test kits. I cant grow most plants (around 80% of new varieties i buy will wither away). I would like to, however but its not practical for me to use ro or distilled water. Is there really no other way?


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## Roger Miller (Jun 19, 2004)

There are a lot of problems that could cause your plants to wither away. Hardness is not the most likely problem, A lot of people manage to grow plants in hard water.

If your really want to "freshen" your water then deionization is an alternative, but in the long run deionization is more expensive than RO. Have you considered using rain water to dilute your supply?


Roger Miller


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## ASD (Feb 8, 2003)

Growing plants in hard water can be a bit difficult. I have an african cichlid planted tank. Adding CO2 has been very helpful for the plants (anubias, crinum thaium, vals). My KH is 13 and GH 7-10. Some plants can handle the hard water, others will certainly not.
-ASD

ASD


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## Glazen (Apr 27, 2003)

My tank has a pH of 5.8 and KH is at only 2! Am i oversupplying the Co2? Does a low KH means that it is too acidic? 

What is the recommended supply of Co2?

Excuse me for putting up these simple question here as i am juz a beginner.

Any help will be much appreciated.


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## ASD (Feb 8, 2003)

You probably want a kH higher than 2. This will stabilize pH, and allow you to add more CO2 with less of a pH drop. Your pH should probably be above 6.2 or so. 5.8 is pretty acidic. Here is a great page that discusses pH, kH, and CO2:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

ASD


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## ASD (Feb 8, 2003)

To further the point

pH can be measured by the Henderson-Hasselbach equation, stating pH=log([base]/[acid])

The base, in our case, is the ammount of carbonate, or kH. The acid is carbonic acid, which is formed when CO2 is dissolved in water.

The page above has an online program that will do these calculations. Who knew chemistry could be so useful.

ASD


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