Gh? - The Planted Tank Forum
 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old 01-02-2006, 10:05 PM Thread Starter
Guest
 
PTrader: (4/100%)
Join Date: Apr 2004
Posts: 443
Gh?

How do you convert GH ppm in GH degrees?, my GH tested 180 ppm, how much is that in degrees?, thanks
tiny is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 01-02-2006, 11:11 PM
Planted Member
 
PTrader: (0/0%)
Join Date: Oct 2003
Location: Littleton, CO
Posts: 279
Divide the ppm by 17.9 to get degrees
emoore3 is offline  
post #3 of 11 (permalink) Old 01-03-2006, 05:10 AM
Wannabe Guru
 
Hypancistrus's Avatar
 
PTrader: (0/0%)
Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
It depends on what standard your test kit is measuring. Most GH test kits measure in a calcium carbonate standard. In other words, even if you have no calcium carbonate in your water, the test kit is measuring GH as if it were all coming from calcium carbonate.

"Degree" is a German measurement based on the measurement of calcium in calcium oxide. One degree equals an equivalent of 10 ppm of calcium oxide.

Based on atomic weights, 10 ppm of calcium oxide is 7.15 ppm of calcium and 2.85 ppm of oxygen.

To carry this over to calcium carbonate so that you also get 7.15 ppm of calcium, you need 17.86 ppm of calcium carbonate. This contains 7.15 ppm of calcium and 10.71 ppm of carbonate.
Hypancistrus is offline  
 
post #4 of 11 (permalink) Old 01-03-2006, 02:36 PM Thread Starter
Guest
 
PTrader: (4/100%)
Join Date: Apr 2004
Posts: 443
I have no clue, can you just tell me if a GH of 180 ppm is a good reading?
tiny is offline  
post #5 of 11 (permalink) Old 01-03-2006, 04:07 PM
Wannabe Guru
 
Hypancistrus's Avatar
 
PTrader: (0/0%)
Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Well if you're doing a GH test with a test kit, it should definitely tell you somewhere what equivalent it's actually testing for. Most likely it is calcium carbonate.

In that case, you are at about 10 degrees GH. In my poll thread:

https://www.plantedtank.net/forums/sh...ad.php?t=24774

So far, people voted for 3, 5, and 6. I do 6. If your plants look OK, I wouldn't worry about it.
Hypancistrus is offline  
post #6 of 11 (permalink) Old 01-03-2006, 11:15 PM Thread Starter
Guest
 
PTrader: (4/100%)
Join Date: Apr 2004
Posts: 443
Sounds good, thanks
tiny is offline  
post #7 of 11 (permalink) Old 02-08-2006, 07:11 PM
Planted Tank Enthusiast
 
banderbe's Avatar
 
PTrader: (5/100%)
Join Date: Oct 2005
Location: Maple Grove, MN
Posts: 502
Quote:
Originally Posted by Hypancistrus
It depends on what standard your test kit is measuring. Most GH test kits measure in a calcium carbonate standard. In other words, even if you have no calcium carbonate in your water, the test kit is measuring GH as if it were all coming from calcium carbonate.

"Degree" is a German measurement based on the measurement of calcium in calcium oxide. One degree equals an equivalent of 10 ppm of calcium oxide.

Based on atomic weights, 10 ppm of calcium oxide is 7.15 ppm of calcium and 2.85 ppm of oxygen.

To carry this over to calcium carbonate so that you also get 7.15 ppm of calcium, you need 17.86 ppm of calcium carbonate. This contains 7.15 ppm of calcium and 10.71 ppm of carbonate.
So it is possible that my GH test kit is telling me about only Magnesium? My water goes through a water softener and afterwards has a GH of about 5. I have been trying to figure out how much calcium if any is left in that water, short of buying a calcium test kit. I thought 1 dGH was always composed of a ratio of Calcium and Magnesium.

Regards,
Barry
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


FILSTAR Advocate #39
Member, Minnesota Aquarium Society
29 Gal. - 100% Eco-Complete/2x65W CF/CO2/Filstar XP2/RedSea500/KH:3/GH:5/pH:< 5.5/EI Dosing/WWC 50%
banderbe is offline  
post #8 of 11 (permalink) Old 02-08-2006, 11:33 PM
Guest
 
PTrader: (0/0%)
Join Date: Feb 2006
Posts: 5
How to convert ppm of baking soda into KH degrees? Is this the amount of bicarbonate equivalent to 10.71 ppm of carbonate equivalent to 7.15 ppm of calcium equivalent to 10 ppm of calcium oxide?
dm01 is offline  
post #9 of 11 (permalink) Old 02-09-2006, 12:14 AM
Wannabe Guru
 
Hypancistrus's Avatar
 
PTrader: (0/0%)
Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
banderbe, it's hard to tell at that point. My understanding is water softeners that use table salt (sodium chloride) exchange calcium and magnesium ions with sodium ions. I don't like them because they don't actually remove ions, just exchange them, so they produce water very rich in sodium.

I don't know of any calcium test kits that only test for calcium and not magnesium at the same time. You could have your water company run a test using ion probes, or American Marine developed a "dip and read" ion selective probe meter for calcium. However, it costs $250, and is really aimed more at reef tanks (i.e., tanks with very high calcium levels).

dm01, I'm not sure what you are asking. Here's all the math, I don't really know how to make it any clearer:

German standard is 1 dGH = 10 ppm of Calcium Oxide (CaO)

Calcium = 40.078 grams per mole
Oxygen = 15.9994 grams per mole
Carbon = 12.0107 grams per mole
(atomic masses from the periodic table)

CaO = 56.0774 grams per mole (40.078 + 15.9994)

10 ppm CaO = 1 dGH

71.46908 % Calcium (40.078 / 56.0774)
28.53092 % Oxygen (15.9994 / 56.0774)

1 dGH contains

7.146908 ppm Calcium (71.46908 % x 10 ppm)
2.853092 ppm Oxygen (28.53092 % x 10 ppm)

Carbonate has no calcium, so we must use a standard of calcium carbonate to get degrees of hardness for carbonates

CaCO3 = 100.0869 grams per mole (40.078 + 12.0107 + 15.9994 + 15.9994 + 15.9994)
CO3 = 60.0089 grams per mole (12.0107 + 15.9994 + 15.9994 + 15.9994)

40.04320 % Calcium (40.078 / 100.0869)
59.95680 % Carbonate (60.0089 / 100.0869)

X * .4004320 (percent of calcium in calcium carbonate) = 7.146908 ppm calcium (ppm of calcium in 1 degree)

Solve for X

X = 17.84799 ppm Calcium Carbonate in 1 dKH

17.84799 ppm * .5995680 (percent of carbonate in calcium carbonate) = 10.701084 ppm Carbonate in 1 dKH
Hypancistrus is offline  
post #10 of 11 (permalink) Old 02-09-2006, 12:24 AM
Wannabe Guru
 
Hypancistrus's Avatar
 
PTrader: (0/0%)
Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
For baking soda, calculate the ppm in carbonate, then multiply by 10.701084 to get degrees.

Sodium Bicarbonate - NaHCO3

Sodium = 22.989770 g/mole
Hydrogen = 1.00794 g/mole
Carbon = 12.0107 g/mole
Oxygen = 15.9994 g/mole
Carbonate = 60.0089 g/mole
Sodium Bicarbonate - 84.00661 g/mole

Carbonate:
1 / (60.0089 / 84.00661) = 1.399903 mg to raise carbonate 1 ppm in 1 liter
1.399903 * 10.701084 = 14.980480 mg to raise carbonate 1 dKH in 1 liter
14.980480 * 3.785412 = 56.707287 mg to raise carbonate 1 dKH in 1 gallon
Hypancistrus is offline  
post #11 of 11 (permalink) Old 02-09-2006, 01:37 AM
Guest
 
PTrader: (0/0%)
Join Date: Feb 2006
Posts: 5
Quote:
Originally Posted by Hypancistrus
For baking soda, calculate the ppm in carbonate, then multiply by 10.701084 to get degrees.

Sodium Bicarbonate - NaHCO3

Sodium = 22.989770 g/mole
Hydrogen = 1.00794 g/mole
Carbon = 12.0107 g/mole
Oxygen = 15.9994 g/mole
Carbonate = 60.0089 g/mole
Sodium Bicarbonate - 84.00661 g/mole
Hypancistrus, many thanks for additional info. Thus, based on the atomic weights ratio of sodium bicarbonate and calcium carbonate (84/100) I would need to use 15 ppm of baking soda to have as much carbonate as I would have with 17.9 ppm of CaCO3 (which is equivalent to 10.7 ppm of carbonate). And this would be 1 degree KH. Right? Now, does the electric charge of ions matter for defining water hardness (a single negative charge of a bicarbonate ion versus two of a carbonate ion)?
dm01 is offline  
Reply

Tags
None

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome