ro - increasing hardnes !!! - The Planted Tank Forum
Old 11-22-2005, 08:23 PM Thread Starter
Algae Grower

Join Date: Nov 2005
Location: Świdwin
Posts: 64
ro - increasing hardnes !!!

halo all.
I want to add 20 ppm of ca using caco3 and 5 ppm of mg using mgso4x7h2o.

Witch hardness i can reach?

I need about 4 gh and 5 kh.
andkoni is offline

Old 11-22-2005, 08:40 PM
Wannabe Guru

Join Date: Aug 2003
Location: Dallas
Posts: 1,018
Quote:
Originally Posted by andkoni
halo all.
I want to add 20 ppm of ca using caco3 and 5 ppm of mg using mgso4x7h2o.

Witch hardness i can reach?

I need about 4 gh and 5 kh.
to start you off, there is 17.9ppm per dGH and dKH.
So you are looking for 72ppm GH and 90ppm KH.

Also keep in mind that adding 5ppm Mg does not equate to 5ppm GH, it is actually 4.1x different. 5ppm Mg = 20.5ppm GH.

So to get to 72ppm GH, dose 50ppm of Ca (from CaCO3) and 5ppm Mg.

You get an equivalent of 30ppm CO3 when dosing CaCO3 with 20ppm Ca, so you will get to 75ppm CO3 with the amount of CaCO3 dosing recommended above, meaning you will need 15ppm more, which you can do by dosing Baking Soda (Na2CO3).

With Baking Soda, it takes 1 teaspoon per 50g's (US gallons) to increase KH by 18ppm.

Cliff
450g Planted Discus Tank - Work in Process!
Spar is offline
Old 11-23-2005, 05:04 AM
Wannabe Guru

Join Date: Sep 2004
Location: San Francisco (mainland transplant from Hawaii)
Posts: 1,464
correct me if I am wrong but dolomite (CaCO3) actually has Mg in it. From my understanding there is no real way of telling how much magnesium is actually in your dolomite mix. So Spar your calculations may be wrong. It would work with calcium chloride but not calcium carbonate. Anybody else want to chime in?

Ian
ianiwane is offline

Old 11-23-2005, 05:15 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Quote:
Originally Posted by Spar
to start you off, there is 17.9ppm per dGH and dKH.
That's actually incorrect.

A degree of German Hardness is equivalent to 10 ppm of calcium oxide (CaO) or 17.86 ppm of calcium carbonate (CaCO3). CaO contains 7.1469 ppm of calcium and 2.853 ppm of oxygen. CaCO3 contains 7.1469 ppm of calcium and 10.7145 ppm of carbonate (CO3).

Also, there is 4.334 mg/Liter or ppm of magnesium per German degree of hardness.
Hypancistrus is offline
Old 11-23-2005, 05:22 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Quote:
Originally Posted by ianiwane
correct me if I am wrong but dolomite (CaCO3) actually has Mg in it. From my understanding there is no real way of telling how much magnesium is actually in your dolomite mix. So Spar your calculations may be wrong. It would work with calcium chloride but not calcium carbonate. Anybody else want to chime in?

Ian
How are you getting that CaCO3 has magnesium in it? It could have traces of magnesium in it, which may possibly be the case if you use agricultural grade powder. If you get Reagent ACS grade from a lab supplier, the impurity or "trace" levels will (or should) be listed on the label.

Anyway, use the formulas as a starting point, then adjust based on what your actual test readings are.
Hypancistrus is offline
Old 11-23-2005, 05:23 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
You might find this helpful, I posted this on another forum... I really recommend using CaCl2 instead of CaCO3 because it gives you the ability to control KH and GH separately.

To raise gH by 1 dgH in 1 gallon of water using calcium chloride dihydrate and magnesium sulfate heptahydrate while maintainig a 4:1 ratio of calcium to magnesium cations:

- Add 0.07939 grams of CaCl2*2H2O
- Add 0.03328 grams of MgSO4*7H2O

Use this as a starting point. There are other factors that will affect the actual gH reading - calcium and magnesium cations may not register 100% equally on your test, the quality of the compounds used (agricultural grade from Greg Watson vs. reagent ACS grade from a lab supplier), compounds in your specific water chemistry - so simply adjust the measurement by using the same percent of each. (Example, if it raises it a bit more than you wanted, try multiplying each measurement by .75 to dose at 75% strength next time.)

DO NOT DISSOLVE CaCl2 and MgSO4 IN THE SAME CONTAINER! - The calcium and sulfate ions will bind and calcium sulfate will precipitate out. Calcium Sulfate is "insoluble" - it will dissolve but verrryyy sloowwllly.

-------------------------

Calculations - Assumes an EDTA chelation gH test in which calcium and magnesium cations register equally

- Calcium = 40.078 g/Mole

- CaCl2*2H2O Dihydrous Calcium Chloride = 147.01396 g/Mole

- Magnesium = 24.305 g/Mole

- MgSO4*7H2O Heptahydrate Magnesium Sulfate = 246.47556 g/Mole

1 dGH (Degrees of German Hardness) for calcium = 7.14691 ppm or mg/Liter / 1000
= .00714691 g/Liter / 40.078 g/Mole = .00017832 Moles

1 dGH (Degrees of German Hardness) for magnesium:
.00017832 * 24.305 = .0043342 g/Liter * 1000
= 4.33419 mg/Liter or ppm

Increasing 1 dGH of Calcium (7.14691 ppm) in 1 liter of water using Dihydrous Calcium Chloride:
7.14691 / (40.078 / 147.01396) = 26.21626 mg/Liter

Increasing 1 dGH of Magnesium (4.33419 ppm) in 1 liter of water using Heptahydrate Magnesium Sulfate (Epsom Salt):
4.33419 / (24.305 / 246.47556) = 43.95274 mg/Liter

Converted to Gallons:

Increasing 1 dGH of Calcium in 1 gallon of water using Dihydrous Calcium Chloride:
26.21626 * 3.785412 = 99.23934 mg/Gallon

Increasing 1 dGH of Magnesium in 1 gallon of water using Heptahydrate Magnesium Sulfate (Epsom Salt):
43.95274 * 3.785412 = 166.37924 mg/Gallon

Converted to a 4 : 1 ratio of calcium : magnesium

99.23934 mg/Gallon CaCl2 = 1 dGH
166.37924 mg/Gallon = 1 dGH

79.39147 mg/Gallon = .80 dGH
33.27585 mg/Gallon = .20 dGH
Hypancistrus is offline
Old 11-23-2005, 06:59 AM Thread Starter
Algae Grower

Join Date: Nov 2005
Location: Świdwin
Posts: 64
ok. I will be have 4gh and a want to add 15 ppm K using K2co3.
witch kh i can reach together ?
andkoni is offline
Old 11-23-2005, 01:33 PM
Wannabe Guru

Join Date: Aug 2003
Location: Dallas
Posts: 1,018
Quote:
Originally Posted by Hypancistrus
That's actually incorrect.

A degree of German Hardness is equivalent to 10 ppm of calcium oxide (CaO) or 17.86 ppm of calcium carbonate (CaCO3). CaO contains 7.1469 ppm of calcium and 2.853 ppm of oxygen. CaCO3 contains 7.1469 ppm of calcium and 10.7145 ppm of carbonate (CO3).

Also, there is 4.334 mg/Liter or ppm of magnesium per German degree of hardness.
Other than the 4.334 ppm of Mg issue, I don't see where our math is different? He is dosing CaCO3, not CaO.

As for the MgSO4+7H20, don't forget about Molecular weight issues. That is where the issue of having the 4.1x factor comes into dosing. There are a couple posts explaining it around.

You said "CaCO3 contains 7.1469 ppm of calcium and 10.7145 ppm of carbonate (CO3)". How much CaCO3 (1 gram?) and into how much water is this the case?

Cliff
450g Planted Discus Tank - Work in Process!
Spar is offline
Old 11-23-2005, 08:17 PM
Wannabe Guru

Join Date: Sep 2004
Location: San Francisco (mainland transplant from Hawaii)
Posts: 1,464
well, the stuff we get from greg watson is actually dolomite which is calcium magnesium carbonate not calcite which is calcium carbonate. Its clearly labeled on the greg watson ferts as dolomite. Link to info on dolomite http://mineral.galleries.com/mineral...e/dolomite.htm
ianiwane is offline
Old 11-24-2005, 04:09 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Ah, I learn something new every day. I didn't know that the calcium carbonate that Greg Watson sold was dolomite. I should learn to read descriptions more. He does make an error in the forumla for dolomite - it's CaMg(CO3)2, not CaMgCO3.

The general wisdom is that calcium should be dosed in a 3:1 to 4:1 ratio to magnesium.

With dolomite, this is not possible.

In dolomite, magnesium is bound to calcium in a 1.65:1 ratio based on molecular weight and EDTA chelation testing. So for every degree of GH that you raise the water with dolomite for calcium, you will raise it by 1.65 degrees for magnesium.

To raise GH by 1 dGH with dolomite, you would add 31.06 milligrams per gallon of water. (62% from magnesium, 38% from calcium.)

This dose will also raise the alkalinity by half a degree (.49840 dKH increase).

Using calcium chloride, magnesium sulfate, and sodium bicarbonate, it is possible to control ca, mg, and co3 levels individually.

----- Work / Calculations ----

Calcium = 40.078 g/mole

Magnesium = 24.305 g/mole

Carbonate (CO3) = 60.0089 g/mole

Dolomote (CaMg[CO3]2) = 184.4008 g/mole

1 dGH for calcium = 7.14691 ppm

1 dGH for magnesium = 4.33419 ppm

1 dKH for carbonate = 10.7145 ppm

Increase 1 dGH of magnesium & calcium in a locked 1.65:1 mg:ca ratio using dolomite (CaMg[CO3]2):

Calcium = 7.14691 ppm / (40.078 g/mole / 184.4008 g/mole) = 21.73418 mg/Liter

Magnesium = 4.33419 ppm / (24.305 g/mole / 184.4008 g/mole) = 13.18053 mg/Liter

Ratio = 21.73418 / 13.18053 = 1.64896 : 1 (Mg : Ca)

21.73418 mg adds 1 dGH for calcium & 1.64896 dGH for magnesium

21.73418 mg = 2.64896 dGH total

8.20479 mg = 1 dGH (.62249 dGH from Magnesium & .37751 dGH from Calcium)

Converted to Gallons:

8.20479 mg * 3.785412 liters/gallon = 31.05851 mg

For Carbonate:

10.7145 ppm CO3 = 1 dKH

10.7145 ppm / (120.0178 g/mole / 184.4008 g/mole) = 16.46224 mg/Liter

8.20479 mg / 16.46224 mg = 0.49840 dKH
Hypancistrus is offline
Old 11-24-2005, 04:19 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Quote:
Originally Posted by Spar
As for the MgSO4+7H20, don't forget about Molecular weight issues. That is where the issue of having the 4.1x factor comes into dosing. There are a couple posts explaining it around.
Check my calculations, they fully take into account and are based on molecular weights.
Hypancistrus is offline
Old 11-24-2005, 12:51 PM
Banned

Join Date: Dec 2002
Location: Some where in SOCAL
Posts: 1,638
WOW!!! I am amazed at all of the adding of this and that measuring hear and there just to increase gH and kH.

I like to keep it simple, Add TAP WATER until you reach the amount of gH and kH. It's easier and faster instead of adding chemicals. More natural too. But if there is something wrong with your water you get from the tap then I understand the need to add chemicals.

In my area I have extremely high gH and kH so I would add about 50% tap and the rest would be RO water. Then I would test and decide where to go from there.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
aquaphish is offline
Old 11-24-2005, 02:26 PM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
It's a lot like economics. Lots of formulas and precise numbers out to several decimal places, but in the end it's mostly theory and estimation. I think of it as basically a starting point. Don't let the calculations phase you, it's really not much more than high school level math and it's only there to show how I arrived at my results.

If you do RO water then mix it with tap water to target your GH, I see absolutely nothing wrong with that technique, it's just another method or preference.

But it seems there's so many threads that follow the lines of, "I just got such and such from Greg Watson, how much do I add to get X ?" There's a direct and simple answer, yet so often it seems these types of threads grow into the multi pages and the correct numbers never end up getting posted.
Hypancistrus is offline
Old 11-25-2005, 10:30 PM
Guest

Join Date: May 2005
Posts: 21
Hi guys,

Your knowledge amazed me. However, are you guys taking about a tank with only plants in it? Because if you have any fish in it, I am sure they would not be healthy with all the compounds of chemical. My philosophy is "KISS".
Kenny_123 is offline
Old 11-26-2005, 12:34 AM
Wannabe Guru

Join Date: Oct 2004
Location: West Michigan
Posts: 1,032
Quote:
Originally Posted by Kenny_123
Hi guys,

Your knowledge amazed me. However, are you guys taking about a tank with only plants in it? Because if you have any fish in it, I am sure they would not be healthy with all the compounds of chemical. My philosophy is "KISS".
Many many people here (including myself) regularly use these compounds and keep very healthy fish and plants.
Hypancistrus is offline

 Tags None

Message:
Options

## Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.

User Name:
OR