# Safe KH range?



## bms (Feb 19, 2004)

I have started measuring my Ph and Kh levels to find out the concentration of CO2 on my water...

I had noticed neither the Ph nor the Kh are suffering any strong variations... Ph remained around 6.8 and Kh at 7.

Yesterday I added Baking Soda to my CO2 mix, to supposedly (I am still experimenting) get a more steady production of CO2... and voila this morning my Kh was up to 9.

I read that Baking Soda has this effect... but, what levels of Kh are safe? Should I be concerned with the Kh values by themselves or only by the resulting CO2 concentration? If I need to control (reduce) my KH how do I accomplish that?

I guess I need to understand a little better not only the relation amongst this measurements but their causes and relationships to plant healt and tank maintenance. 

I appreciate any references guidelines.


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## IUnknown (Feb 24, 2004)

More than your KH I would be concerned with your pH. Baking soda causes higher pH values without Co2 injection, so if the Co2 stops your pH is going to fluctuate a lot. So just make sure Co2 is going 24-7.


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## bms (Feb 19, 2004)

Well I added Baking Soda to my DIY CO2 system, not to the tank itself. 

I assumed this had some effect on my Kh in the tank, even though the BS is not in direct contact with the tank water.

But I get your point... the only thing that matters is the CO2 concentration and the Ph values that both plants and fish can support keeping the former in "normal" ranges will always produce an acceptable KH level... is this logic correct?


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## tsunami (Jan 24, 2004)

Benicio,

Do you still have those limestone rocks in the tank? Those could be raising your KH.

The water coming out of my tap here is at KH 4, GH 5.

Carlos


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## bms (Feb 19, 2004)

Nope I removed most of them them... I left some in there... including the black one on this picture:

http://www.aquaticplantcentral.com/forum/download.php?id=129

Is this one safe?


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## bms (Feb 19, 2004)

Nope I removed most of them them... I left some in there... including the black one on this picture:

http://www.aquaticplantcentral.com/forum/download.php?id=129

Is this one safe?


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## dennis (Mar 1, 2004)

Bms,
I don't think adding baking soda to your yeast mix will raise the kh of your tank. The purpose of the soda wihtt he yeast is to slow down fermintation iniatally and there for make the reaction last longer. IT also helpsa buffer the Mix so that the bacteria(yeast) can live a bit longer. I would assume that there is another cuase for you tank kh raising. I use the same method as you adn have never had my kh raise until I add baking soda to my tank its self. I have a kh of 2 and it stays at 2 until I add something. Your water is pretty well buffered so I would not worry to much about it


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## bms (Feb 19, 2004)

My concern with such a high Kh is that my Ph will have to be high as well to maintain a safe Ph...

Now, assuming I reduce the amount of CO2 I inject... the CO2 concentration would be less, but what is expected in regards to Kh / Ph readings?


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## aquoi (Mar 21, 2004)

Adding sodium bicarbonate to DIY yeast mixture is actually to raise the KH of the mixture and increase the buffering capacity so the pH won't drop too low and kill the yeast culture.


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## dennis (Mar 1, 2004)

Aquoi is right aboutuhe yeast mixture but it seems you are concerned about your tanks ph. Well lets start with what you have know. kH 7` and pH of 6.8 gives you 33ppm of co2. That is perfect. Also 6.8 is a fine ph. You should be able to grow most plants and all of the common ones. There might be some rarer species that like much higher or much lower...but you get the idea. Everything is ok so far.

In comparison, your water, wihtout co2 injection, as you would find it in local rivers, streams, etc(not accounting for extra dissolved minerals and such, which should not matter much in this case anyway) would have a pH of 7.6 to 7.8. Not uncommen and all the local plants, fish and other creatures survive in this fine. Still nothing to worry about.

You also must remember that in nature there are many and wide flucuations both wiht ph and also to a lesser degree kh and gh. Rains, flood, dryspells all cause the flucuations of various concentrations in the local water.....and the floura and fauna handle it fine SO don't worry to much. The occasional flucuation is fine and unless you keep very delicate species you should have nothing to worry about.

It seems that your confusion about the kH/pH relationship is based on the fact that the mathimatical fomula for computiong it is some kind of sliding logrithim or something. Complex math

I would recomend checking out CHuck Gadd's site and also downloading the calculator from it. IT is acurate and extreemly handy. http://www.csd.net/~cgadd/aqua/index.htm Read his article about the ph/kh relationship. It is pretty well written.

In short bms, odn't worry to much. Try to be consistant wiht you co2 but don't sweat it if you need to change the mix or do a wc. The fish will be just fine, as will the plants.

As for your kH rise, there must be a cause other than the BS in the yeast mix. CO2 forms and acid in water, which is why your ph drops and your co2 line getts funny at the end, and the stronger acid can cause some materials to disolve faster. If you have and rock in your tank, or shells or anything that might have a Calcium base then that is probably your culprit, The lower ph cuases it to dissolve faster and release ions that raise the kh. Remove anything that might do this and you should be fine. Also, keep an eye on your kh. if it does not change any more or goes back to normal, you could attribute it to a change in your water supply. My tap water reciently changed to a consistant kh3 to kh2. these things happen.

Whew.....Sorry for the long post. I hope it helped.


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## bms (Feb 19, 2004)

Thanks for the information... I will read the references you posted. I am a bit concerned I have something in my tank that is rising the Kh... I removed some stones that where limestones and left some others there I tested with vinager and didn't fizz so I thought they were OK...

But, I tested my tap water this morning Ph 7.8 and Kh 2! There must be something in my tank causing the Kh to rise.

I am going to take pictures of all my stones and see if someone can tell me if they are safe to use.


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## dennis (Mar 1, 2004)

Muratic acit would be better to use than vinegar. Vinegar is not very strong.


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## aquoi (Mar 21, 2004)

Anti-chlorine?
Fish food?
Gravel? Filter media?
Additives?

These could all be potential culprits.


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