# How much Epsom Salt to rule out Mg deficiency?



## nasfish (Sep 26, 2005)

hi,

Wihout knowing my GH, after weekly 50% WC, how much Epsom Salt to use to rule out Mg deficiency? My tank is 60 gal.

Thanks in advance.


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## Edward (May 25, 2004)

Dose 4 ml daily of Mg solution made by mixing 170 grams MgSO4 in 500 ml water.
This will add 0.56 ppm Mg daily, maintaining 2 ppm or 0.5 dGH at 50% weekly WC.


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## MrSanders (Mar 5, 2006)

I have been wondering the same thing, I have had odd issues with plant growth for a while now... Most recently they have really been coming out with my rotala r. with older leaves having dark green veins. along with yellowing of the leaf and and brown areas forming into holes... not really pin holes, just dead areas.

Anyway I have started adding epsom salts but didnt really know how much it would take as some seem to add a lot, and others say you only need a very small amount. 

Is there any reason for adding Mg daily? rather than say just adding 4 ppm Mg at water change?


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## nasfish (Sep 26, 2005)

Thanks Edward.

But what if I want to dose it after 50% WC weekly?. Oh yeah MrSanders, I have been wondering it too. And what if I want to dose Epsom Salt without making it to a solution first, 1/4tsp? 1/2tsp? 1tsp? grams? 

Feedback really appreciated

Thanks


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## Edward (May 25, 2004)

Look around, what kind of people post problems most of the time? 
People using spoons.


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## Jason Baliban (Feb 21, 2005)

Edward said:


> Look around, what kind of people post problems most of the time?
> People using spoons.


That might be the million dollar phrase of the week.

jB


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## nasfish (Sep 26, 2005)

Beleive me, I have been looking around before, searching the forum for 'Epsom Salt', 'Mg Dosing', 'Magnesium", etc but get a lot more confusing info. Can't seems to get the straight answer. Also the previous post have different situations, as every tank is different from others. I can re-post all the confusing answers from previous posts here, but it is too long!, and a lot confusing. So back to the original question, short and straight answer is much appreciated.

Best Regards

Thanks


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## MatPat (Mar 22, 2004)

Edward said:


> Dose 4 ml daily of Mg solution made by mixing 170 grams MgSO4 in 500 ml water.
> This will add 0.56 ppm Mg daily, maintaining 2 ppm or 0.5 dGH at 50% weekly WC.


nasfish,
I think Edward answered that for you in his first post


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## wiste (Feb 10, 2006)

The recommendation to avoid magnesium deficiency is to perform daily dosing.
When adding supplements for your plants, feed your plants like you feed your fish.
Use daily dosing instead of a large dose "delivered with a spoon" when you change the water.


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## jrIL (Apr 23, 2005)

MatPat said:


> nasfish,
> I think Edward answered that for you in his first post


I could be wrong but I think he is asking how much dry should he dose daily in teaspoons. I get the impression he does not want to mix up anything. I am interested as well.

JR


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## Bert H (Mar 2, 2004)

FWIW, I add 1tsp of Mg to each of my 50's twice a week. I have hard, predominantly Calcium containing water.


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## Jason Baliban (Feb 21, 2005)

I have hard water where i live. For the longest time, I was cutting tap with RO. I was adding a certain amount of mg to prevent some leaf curling. Recently I switched to straight tap, and I found that I had to add even more mg to prevent this curling effect.

Is there a balance that must be maintained between calcium and mg? Would we say that the amount available to plants is important, but not as important as the ratio to mg:calciam(similar to the ratio of N)?

jB


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## Bert H (Mar 2, 2004)

I remember reading somewhere that high Ca levels can affect Mg uptake. So this could explain why you would needed to add more Mg when you switched to straight tap. I think with high Ca, somewhere around 3:1 Ca:Mg would be fine. 

I have also read reports saying that what some people attribute to Mg deficiency, you can cure by the addition of boron. I have been thinking of trying this out in my tanks for a while, but haven't gotten around to it because the extra Mg seems to have solved the issues I once had with stunting/curling leaves.


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## wiste (Feb 10, 2006)

Edward said:


> Dose 4 ml daily of Mg solution made by mixing 170 grams MgSO4 in 500 ml water.
> This will add 0.56 ppm Mg daily, maintaining 2 ppm or 0.5 dGH at 50% weekly WC.





jrIL said:


> I could be wrong but I think he is asking how much dry should he dose daily in teaspoons. I get the impression he does not want to mix up anything. I am interested as well.
> 
> JR


Conversion - (4ml /500 ml)*170 grams = 1.36 grams.
Measuring with digital scales 2*1/8 teaspoons of MGS04 gives 1.3 grams
This would be 1/4 teaspoon a day or about 1 tsp twice a week.



Bert H said:


> FWIW, I add 1tsp of Mg to each of my 50's twice a week. I have hard, predominantly Calcium containing water.


My understanding, PPS uses daily dosing.
Standard equipment: digital scale, a pipette with 1ml graduations, and glass jars with lids.

The 4ml is higher than that listed in PPS faq.
50 gall / 200 liter ) 12 drops Mg
( 75 gall / 300 liter ) 1 ml Mg
If no signs of improvement are seen, back off to lower doses?


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## nasfish (Sep 26, 2005)

Thanks guy for overwhelming responses. This forum is the first thing I open when I swicth on my computer.

Yes, Edward answered my question in his first post. Thanks MatPat for pointing that out. And thanks again Edward. Only if I have a digital scale to get the right amount. Using teaspoon seems to be a lot easier. Originally I am thinking of weekly Mg dosing right after weekly 50% WC. But as wiste said, the recommendation to avoid magnesium deficiency is to perform daily dosing, I might change my mind. Thanks wiste.

FYI, I am asking this question just to rule out Mg deficiency. It is not that my tank have any problem with Mg, don't know what to look for if there is any deficiency anyway.

So, for a start, I will dose 1 tsp right after weekly 50% WC, and another 1 tsp 3 days later. I hope that is enough to rule out Mg deficiency for my tank. What do you guys think?

Best Regards

Thanks


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## Edward (May 25, 2004)

Hi
The first reason why daily dosing works better is because Mg is a mobile nutrient. Plants would take most of it on the first day and then suffer the rest of the week. 
The second reason is that the Mg strongly contributes to hardness increase. Two times as much as Calcium. Only ~ 4.4 ppm Mg makes 1 dGH. You don’t want to stress your plants. 

Edward


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## nasfish (Sep 26, 2005)

Thanks Edward,

With good reasons as given by you , I am now convinced to dose Mg daily.
My Epsom Salt comes in a 375 grams packet. I don't have a digital scale to get 170 grams as you suggested earlier. So I deicded to use all 375 grams, mixing in 1000 ml water. This will give me approx 0.56 ppm Mg daily, if I were to dose 3 ml daily of the Mg solution made to my 220 liters tank (using Fertilator). Correct me if I am wrong.

Best Regards

Thank You


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## nasfish (Sep 26, 2005)

Hi,

Just found out that the solubility of Epsom Slats (MgSO4) is 35.6 grams per 100 ml water. Obviously 1000 ml water will not dissolved all 375 grams Epsom Salts. Instead, I will mix it into 1500ml water to get 0.56 ppm Mg if I were to dose 5 ml of solution made into my 220 liters tank.

Best Regards

Thank You


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## plantbrain (Jan 23, 2004)

Edward said:


> Look around, what kind of people post problems most of the time?
> People using spoons.


I use spoons, I have no problems.
My spoons are no different than anyone else's.
I could say the same thing about PPS and be correct as well.
But the testing issues, and the CO2 would be much more the reason for both problems using spoons or not. It's not the spoon's fault when you make poor assumptions as to causes of problems.

If you add 1 ppm Mg per 7 ppm of N, you will likely never have any such deficiency with Mg. Note that is elemental mass, not NO3 and MgSO4 * 7H2O.

Whether the nutrient is in solution or dry does not make any difference(it's going to be added to the tank of a known volume anyway, why not use that as the volume instead of dilutions?). It's an added step and this hobby/any method is not that critical to require accuracy to that level except perhaps a tiny nano tank, but I have 9 such tiny tanks without any issues, so.......

I disagree about the need to dose daily for Mg. I do not think it'll hurt either.
You can dose it once a week, I have and can match my plant health against the best out there.

Regards, 
Tom Barr


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## RuslanJamil (Oct 30, 2005)

Edward said:


> Dose 4 ml daily of Mg solution made by mixing 170 grams MgSO4 in 500 ml water.
> This will add 0.56 ppm Mg daily, maintaining 2 ppm or 0.5 dGH at 50% weekly WC.


The 2 ppm Mg at weekly 50% WC is assuming there is no consumption of Mg by the plants during the week, right?


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## Edward (May 25, 2004)

RuslanJamil said:


> The 2 ppm Mg at weekly 50% WC is assuming there is no consumption of Mg by the plants during the week, right?


Correct. 
For 60 gallon aquarium.


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## Edward (May 25, 2004)

For other aquariums you can use this table to rule out nutrient deficiencies. Click hehe for print form.










Example 1: dose daily 10 drops of Mg solution to 10 gallon aquarium.

Example 2: dose daily 4 ml of Mg solution to 75 gallon aquarium.

(Mg solution is made of 169 grams of MgSO4 dissolved in ½ liter water.)


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