# Seachem equilibrium continues to confuse me



## Chlorophile (Aug 2, 2011)

I can't figure this product out what so ever.
Their calculator is in meq/l 
I saw 1 meq/l is 3 German degrees?
So 2.5 GH is .89 meq/l
If I have 2.5gh after WC and want to get back to 5GH I need another .89 meq/l
1.78 meq/l

Plug it in, says 1.4tbsp
Ok cross reference rotalabutterfly
1.4 tbsp x 3 = 4.2 tsp

Yields 
K	32.78
Ca	13.55
Mg	4.05
Fe	0.18
Mn	0.1

So a week's worth of K aside, I've got 13.55 and 4.05... Ca/Mg
I know right off the top of my head that one degree is 17.8ppm..
So the 2.5 degrees turned into less than a degree..

Where in the world and I going wrong here, which calculator is wrong, and how much do I ACTUALLY add to get 2.5 dGH
And how much K does that add?

If rotalabutterfly is right I've been underdosing Ca for literally the entire time I've been on RO.
Yet my test kits read close enough to the seachem calculator math.


----------



## ChrisX (May 28, 2017)

I add 1.5 tsp to 10g of water. That will give + 2 or 3. Don't know how much it increases KH.


----------



## Chlorophile (Aug 2, 2011)

ChrisX said:


> I add 1.5 tsp to 10g of water. That will give + 2 or 3. Don't know how much it increases KH.


It doesn't increase KH at all! 
lol Don't confuse me anymore!


----------



## nilocg (Jul 12, 2010)

Chlorophile said:


> I can't figure this product out what so ever.
> Their calculator is in meq/l
> I saw 1 meq/l is 3 German degrees?
> So 2.5 GH is .89 meq/l
> ...



Hi Chlorophile, I'll have to look up the formula but I dont think dGH is a straight addition. 1ppm mg does not equal 1ppm ca as far as dGH goes.

Bump: I cant find the formula for some reason, but I believe that you have to convert the mg/l to CaCO3 equivalents, then using that number for the 17.9ppm per dGH. I could be explaining it completely incorrect, Im sure @zorfox will know better.


----------



## Immortal1 (Feb 18, 2015)

Don't know if this helps, but;
2.8dGH / 20ppm Ca
or
1.15dGH / 5ppm Mg

I used the above information to generate a spreadsheet to help figure out how much Mg was in the tank.
I can test for Ca in 10ppm increments and I can test for dGH.
If my tests shows 20ppm CA and 4dGH, then I must be pretty close to 5ppm Mg

I was using Equilibrium on my tank at one time but the excess K, and in my case the excess Ca was not helping.


----------



## nilocg (Jul 12, 2010)

7.1ppm Ca is close to 1dGH. 
4.4ppm Mg is close to 1dGH.


----------



## Chlorophile (Aug 2, 2011)

Interesting.. So do both the calculators check out? 
13 and 4 Ca Mg respectively is around 2.5 DGH?


----------



## Whysoserious (Dec 7, 2017)

General hardness is the CaCO3 equivalent.

100.0869 (molar mass of CaCO3) / 40.078 (molar mass of Ca) = 2.497
1ppm of Ca is equivalent to 2.497ppm CaCO3. 

17.848ppm = 1 degree of hardness.

I'll leave the reader to work out Mg (still equivalent to CaCO3 (GH)).

If I add 3 grams of seachem EQ to 100 liters of water, how many ppm of stuff do this add?
EQ contains 8.06% of calcium by weight.

(((amount added in grams * 1000) / liters) * percent by weight)
(((3 * 1000) / 100) * 8.06%) = 2.418ppm Ca.
2.418 / 17.848 = 0.135 dGH.

Note that seachem lists K as potash. So you first need to convert K20 to K using molar mass as described above.


13ppm of Ca = 32.4ppm GH.
4ppm of Mg = 16.5ppm GH.
= 48.9ppm GH = 2.74 dGH.


----------



## Whysoserious (Dec 7, 2017)

Whysoserious said:


> (((amount added in grams * 1000) / liters) * percent by weight)
> (((3 * 1000) / 100) * 8.06%) = 2.418ppm Ca.
> 2.418 / 17.848 = 0.135 dGH.


I missed a step in the maths.

2.418ppm Ca x 2.497 (to convert to CaCO3 equivalent) = 6.03 / 17.848 = 0.34 dGH.


----------



## Chlorophile (Aug 2, 2011)

Whysoserious said:


> I missed a step in the maths.
> 
> 2.418ppm Ca x 2.497 (to convert to CaCO3 equivalent) = 6.03 / 17.848 = 0.34 dGH.


so what does 1.5tbsp seachem equilibrium to 33 gallons add?

I honestly don't know what I'm adding so it's hard to tell if i'm underdosing Ca or Mg


----------



## Whysoserious (Dec 7, 2017)

Well Seachem says that 1.5tbspn(s) = 23.8 grams.

DDG says 33 US gallons = 125L

(((23.8 * 1000) / 125) * 8.06%) = 15.34ppm Ca.
4.58ppm Mg
37.12ppm K
0.21ppm Fe
0.11ppm Mn

15.34ppm Ca x 2.497 = 38.3ppm CaCO3 equivalent.
4.58ppm Mg x 4.118 = 18.86ppm CaCO3 equivalent.
38.3 + 18.86 = 57.16 / 17.848 (ppm > degress) = 3.2 dGH.

Seachem likes to be fancy and uses meq/L. So we need to convert Ca and Mg to meq/L to confirm with Seachem.

15.34 * 0.05 = 0.767
4.58 * 0.0833 = 0.38
0.767 + 0.38 = 1.147 GH meq/L.

Seachem reckons 1.5 tbspn(s) to 33 gal = 0.9 GH meq/L.

IMHO, GH meq/L is a retarded measurement scale for aquariums. To many conversions to get back to, "how much of this is there, how much of this other stuff is there".

Ditch the spoons. Plenty of cheap digital scales around.


----------



## Subjected (Feb 6, 2018)

Ok so I have made a calculator and I entered your info. Ill clean it up and try to upload it.

*From Seachem Equilibrium Website:*
To raise mineral content/general hardness (GH) by 1 meq/L (3 dH), add 16 g (1 tablespoon) for every 80 L (20 US gallons).
You have 1.5 TBSP so (16 + (16/2) ) = 24 grams per 33 gallons 124 Liters.

*From my Calculator*
Total meq/L: 144.126
meq/L in 124 Liters: 1.153
dGH Ca: 2.162
dGH Mg: 1.066
Total dGH: 3.236
Ca to Mg Ratio: 3.339

*If making you own version with dry powders: *
K2SO4: 12.301g
CaSO4: 8.307g
MgSO4: 5.873g
MnSO4: 0.058g
Fe DTPA 11%: 0.227g

*Either of these versions will add in ppm: *
K: 44.190
Ca: 15.480
Mg: 4.636
Mn: 0.115
Fe: 0.217
S: 33.615
dGH: 3.236

*Original info I made the calculator with gotten from: *
"http://www.aquariumlife.com.au"
Thread: KH up solutions, pg 5 post # 68, writen by (unissuh, Moderator)

Here we go, Seachem's reply:
16 grams Equilibrium x 0.0806 Ca = 1.290 g Ca
1.290 g Ca/40.08 g/mol = 0.03219 mol Ca
0.03219 mol Ca x 2 = 0.06438 eq Ca = 64.38 meq Ca
We do the same for magnesium (2.41%) using the atomic weight of 24.312:
16 grams Equilibrium x 0.0241 Mg = 0.386 g Mg
0.386 g Mg/24.312 g/mol = 0.01588 mol Mg
0.01588 mol Mg x 2 = 0.03176 eq Mg = 31.76 meq Mg
Add together: 64.38 + 31.76 = 96.14 meq
Divide this by 80 L and we get 1.2 meq/L
The label says 1.0, so if measured absolutely accurately, the label understates the
amount of hardness added. The label also says one tablespoon per 80 liters, and there
is some flexibility in that instruction. A tablespoon is typically taken as 15 grams of
water, but the density of Equilibrium is greater than that of water, hence the slightly
higher value.
The label also states that one meq/L is approximately 3 dGH. That is a rounded
number. The appropriate conversion factor is 1 meq/L = 2.8 dGH, but nonetheless it is
very close.
The conversion factor of 2.8 is a result of the definition of dGH. One degree of general
hardness is taken to be 10 ppm of CaO. For the purposes of this calculation, we take
ppm and mg/L to be equivalent (and at this dose of Equilibrium, they are fairly close).
Thus:
1 meq/L = 0.5 mmol/L x 56.07 mg CaO/mmol = 28.035 mg CaO/L
28.035 mg CaO/L x 1 dGH/10 mg CaO/L = 2.8 dGH

Last edited by unissuh; 03-02-10 at 12:15 PM.


----------



## Chlorophile (Aug 2, 2011)

Subjected said:


> Ok so I have made a calculator and I entered your info. Ill clean it up and try to upload it.
> 
> *From Seachem Equilibrium Website:*
> To raise mineral content/general hardness (GH) by 1 meq/L (3 dH), add 16 g (1 tablespoon) for every 80 L (20 US gallons).
> ...


Thank you, so it seems like this should work, I'm targeting a 5-6 dGH
Assuming my gH is already a 5-6, removing half the water and adding 2.8 dGH back to the tank should get me back to 5-6 dGH
I wasn't sure if I should be doubling this dose, but I think that would get me to a ~9 dGH


----------



## Subjected (Feb 6, 2018)

*Seachem Equilibrium Calculator ver 1.0*

Calculator written in Open Office Calc. but should open in Excel no problem. Sorry if its a bit complicated to look at :grin2:

TinyUpload.com - best file hosting solution, with no limits, totaly free


----------



## Zorfox (Jun 24, 2012)

It appears to me like Seachem's calculator is incorrect. I have seen other errors before so keep that in mind. 

To convert dGH to Meq, mulitply by 3.215046262046376
To convert Meq to dGH, multiply by 0.3110375150133921

*NOTE: These conversion factors are ONLY for Seachem Equilibrium with the analysis listed!*

adding 1 mg of Equilibrium to 1 Liter of water will 
add the following,

Calcium (Ca)	0.0806 ppm
Magnesium (Mg)	0.0241 ppm
Iron (Fe)	0.0011 ppm
Manganese (Mn)	0.0006 ppm
meq 0.0571659595442512 
dGH 0.017780758 


And now for the supporting math...

Equilibrium has the following percentages,

Soluble Potash (K20)	23.0% (K 19.09%)
Calcium (Ca)	8.06%
Magnesium (Mg)	2.41%
Iron (Fe)	0.11%
Manganese (Mn)	0.06%

Since potassium plays no role in general hardness (only divalent metals) we don't have to include it in our hardness calculations.

For ease of explanation lets now assume Equilibrium is a molecule or atom. If we add 1mg of Equilibrium to one liter of water we will have the following,

Calcium (Ca)	0.0806 ppm
Magnesium (Mg)	0.0241 ppm
Iron (Fe)	0.0011 ppm
Manganese (Mn)	0.0006 ppm

Unfortunately, hobbyists use dGH when speaking of "GH boosters" like Seachem Equilibrium. 1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of water. So how much elemental calcium is that?

The calcium percentage of calcium oxide (CaO) is 71.4691%.

So, 10 (mg of CaO) * 0.714691 (percentage of Ca) = 7.14691 mg of elemental calcium in 10mg of CaO.

By definition ppm Ca is not for elemental calcium but for ppm CaCO3.

Atomic weight CaCO3 = 100

So 7.147 mg/liter of elemental Ca would be expressed as 100/40 * 7.143 = 17.8575 mg/liter(ppm)CaCO3.

1dGH = 17.86 ppm CaCO3 and 7.143 ppm Ca2+.

Finally, 

To convert milligrams to milliequivalents use this formula, meq = (mg x valence) / atomic or molecular weight

Let's convert 0.0806 mg of Calcium to meq,

0.0806 (mg Ca) * 2 (calcium has a valence of 2) / 40.0780 (atomic weight of calcium)
0.0806 * 2 = 0.1612
0.1612 / 40.0780 = 0.0040221567942512 meq

So the Ca portion of Equilibrium contributes 0.004022 meq per mg. 

If we do that for all of the listed elements and add the total we know how many meq there are in 1 mg of Equilibrium.

Potassium K+	0.1909 ppm
(0.1909 * 1) / 39.0983 = 0.00488256522 meq

Magnesium Mg++	0.0241 ppm
(0.0241 * 2) / 24.3050 = 0.0482 meq

Iron Fe++	0.0011 ppm
(0.0011 * 2) / 55.845 = 0.00003939475 meq

Manganese Mn++	0.0006 ppm
(0.0006 * 2) / 54.938045 = 0.00002184278 meq


0.0040221567942512 + 0.00488256522 + 0.0482 + 0.00003939475 + 0.00002184278 = 0.0571659595442512 meq/mg

So now we know that 1 mg of Seachem equilibrium contains a total of,

0.0571659595442512 meq/L
0.017780758 dGH/L

0.0571659595442512 / 0.017780758 = 3.215046262046376

0.017780758 / 0.0571659595442512 = 0.3110375150133921

These conversion factors are ONLY for Seachem Equilibrium with the analysis listed.

to convert dGH to Meq, mulitply by 3.215046262046376
to convert Meq to dGH, multiply by 0.3110375150133921

warning. Check my math before using these numbers.


----------



## Immortal1 (Feb 18, 2015)

"warning. Check my math before using these numbers. "

LOL, I don't even understand you math...


----------



## Zorfox (Jun 24, 2012)

Immortal1 said:


> "warning. Check my math before using these numbers. "
> 
> LOL, I don't even understand you math...


Or I could have said adding 4.5 grams (about 3/4 teaspoon) to every 10 gallons of water adds the following...

dGH 2	ppm 
Meq 6.7	
Ca 9.48	ppm
Fe 0.13	ppm
K 22.9	ppm
Mg 2.8	ppm
Mn 0.0705 ppm

but where's the fun in that! :icon_twis


----------



## Immortal1 (Feb 18, 2015)

zorfox said:


> or i could have said adding 4.5 grams (about 3/4 teaspoon) to every 10 gallons of water adds the following...
> 
> Dgh 2 ppm
> meq 6.7
> ...


lol


----------



## Chlorophile (Aug 2, 2011)

Zorfox said:


> Or I could have said adding 4.5 grams (about 3/4 teaspoon) to every 10 gallons of water adds the following...
> 
> dGH 2	ppm
> Meq 6.7
> ...


Lol this is more up my alley! 
Thank you


----------



## esmrproductions (2 mo ago)

I was having this same issue using the calculator, so I called Seachem and they told me to convert from degrees to mEq/L you need to divide by 2.8.


----------

