# How much Baking Soda



## GTApuffgal (Feb 7, 2005)

Hey Jeff, I can't remember where I read it (here - somewhere!), but 1 teaspoon will raise the KH of 10 gallons by one degree.


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## Rex Grigg (Dec 10, 2002)

GTApuffgal said:


> Hey Jeff, I can't remember where I read it (here - somewhere!), but 1 teaspoon will raise the KH of 10 gallons by one degree.



Bad bad bad advice!!! Please delete!!!


One teaspoon will raise 50 liters/13 gallons of water 4°. So ¼ teaspoon would raise 50 liters/13 gallons by 1°. 

Since most of us don't have ready access to measuring spoons in anything other than 1/8 or ¼ teaspoon size you will have to fudge a bit and use just a hair more than 1/8 teaspoon or just a bit short of ¼ teaspoon to raise 10 gallons of water 1°


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## JeffB (May 5, 2005)

Rexx do you know what that would be in grams. I have a gram scale and am not afraid of it. LOL roud:


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## Rex Grigg (Dec 10, 2002)

Actually I don't. 

Best thing to do is take your baking soda and do a series of weighing over the course of a few days and at different times of day. Then average out those weight/measurements and come to a guesstimate.

You know....... I've got the day off and nothing to do so I guess I will go and get a number.


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## Rex Grigg (Dec 10, 2002)

This is sweet. I just weighed 15 samples. 5 each from the three different containers of baking soda in the house.

1 teaspoon of baking soda weighs 5 grams. So 1 gram of baking soda will raise 50 liters/13 gallons of water 0.8° of kH. Which means that 1 gram of baking soda will raise 10 gallons of water just about 1°.


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## JeffB (May 5, 2005)

Hey Rexx I was about to spend my summer vacation measuring Baking Soda with my wife and kids... Now all I have to do is enjoy the Beach... LOL  

Thanks for the feedback... It is much appreciated!!


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## JeffB (May 5, 2005)

I just stumbled across a posting on a different forum (Aquatic Plant Central) with a link to a KH -> Baking Soda calculator. KH Caluclator roud:


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## jhoetzl (Feb 7, 2005)

Rex Grigg said:


> This is sweet. I just weighed 15 samples. 5 each from the three different containers of baking soda in the house.
> 
> 1 teaspoon of baking soda weighs 5 grams. So 1 gram of baking soda will raise 50 liters/13 gallons of water 0.8° of kH. Which means that 1 gram of baking soda will raise 10 gallons of water just about 1°.



To the Rex website with that info!


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## GTApuffgal (Feb 7, 2005)

Rex Grigg said:


> Bad bad bad advice!!! Please delete!!!


http://www.plantedtank.net/forums/showthread.php?t=15099

#2 in the third post. I have been following this for a month now... Sorry!


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## JeffB (May 5, 2005)

> #2 in the third post. I have been following this for a month now... Sorry!


GTApuffgal , Some times its hard to separate the chaff from the wheat.  

Jeff


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## GTApuffgal (Feb 7, 2005)

JeffB said:


> GTApuffgal , Some times its hard to separate the chaff from the wheat.
> 
> Jeff


No kidding! What's weird is that it has been working for me...


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## Hypancistrus (Oct 28, 2004)

Have you been checking the level with a test kit? If so which one?


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## shalu (Jan 16, 2003)

While estimate is needed when using volume measurements like teaspoons, we should be able to calculate EXACTLY when using weight measurement like grams,

Here is my pure math exercise:
KH 1 degree measures 17.9 CaCO3 equivalent. CaCO3/NaHCO3 = 50/42
therefore 1 deg KH = (17.9/50*42 = *15*) ppm NaHCO3. 

1 gram NaHCO3 in 10 gallon water = 1/37854 = 26.4 ppm = (26.4/*15*=1.76) dKH

hmm... quite a bit off from Rex's estimate(1.76 vs 1), but I can't find anything wrong with my math. Comments from experts/chemists?

I suspect that if I am wrong, I am off by a factor of 2, so should be 0.88 exactly, maybe I misunderstood the chemistry when I used CaCO3/NaHCO3 ratio..... hm.. the more I think about it, the more likely this is the case.


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## KevinC (May 24, 2004)

shalu said:


> While estimate is needed when using volume measurements like teaspoons, we should be able to calculate EXACTLY when using weight measurement like grams,
> 
> Here is my pure math exercise:
> KH 1 degree measures 17.9 CaCO3 equivalent. CaCO3/NaHCO3 = 50/42
> ...


Shalu: You didn't convert the calcium carbonate to sodium bicarbonate correctly - it takes 2 bicarbs to equal one carbonate. Not sure what happened in the last step either, so I'm going to type it out with all the units:

17.9ppm CaCO3 = 17.9mg CaCO3/Liter * 2 moles NaHCO3/1mole CaCO3 (reactivity equivalent) * 83g NaHCO3/100g CaCO3 (corrected to reflect molecular weights) = 29.7 mg NaHCO3/Liter (double the answer from above)

10 gallons water * 4 quarts/gallon * 1Liter/1.0567 quarts = 37.85 liters

To raise the 10 gallons by 1 dKH:

29.7mg NaHCO3/Liter * 37.85 liters * 1 gram/1000mg = 1.12 grams NaHCO3

It takes 1.12 grams of baking soda to raise 10 gallons by 1dKH (0.112 g/gallon-dKH) NOTE: Maybe this is where the error comes in - someone saw 1/1 and thought it was 1tsp/1dKH - it is really about 1g/1dKH in 10 gallons!

Since Rex did an excellent experiment, we can say 5 grams baking soda = 1 teaspoon, so 1 teaspoon would raise 10 gallons by 4.5 dKH (5 grams/10 gallons * 1 gallon-dKH/0.112 grams).

I use a rough teaspoon of baking soda per 15-gallon water change on my 72-gallon tank to stay about 4dKH.

Kevin


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## shalu (Jan 16, 2003)

KevinC said:


> Shalu: You didn't convert the calcium carbonate to sodium bicarbonate correctly - it takes 2 bicarbs to equal one carbonate.


Bingo! I guessed how I was wrong while you were typing your message :tongue: 0.89 it is, (1/1.12). My molecular weight ratio was also slightly off, the darn hydrogen is an oddball, forgot my chemistry, so I got 0.88.


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