# do you dose magnesium sulphate



## XbrandonX (Nov 22, 2007)

well.. do you?

if so why, what's the benefit exactly?

if not, why?


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## Will (Jul 24, 2008)

The benefit is that plants need magnesium. They just only need minute amounts of it.

The reason someone would or would not dose it, is dependant on if the source water has it.

Generally if you have hard tap water, you already have sufficient calcium and magnesium.

If you have soft water, you'll maybe want to dose both of those once right after weekly waterchanges. Maybe again later if your WC are not frequent.They aren't something that is needed to be dosed daily or bi-daily. I know from personal experience that overdosing magnesium will cause leaves to curl up.


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## Rmwbrown (Jan 22, 2009)

Yep... In my GH booster.. a must if your using RO/DI water..


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## Kan (Nov 12, 2011)

I think I read somewhere that plants need magnesium in order to absorb iron. Don't quote me on it though, I can't find the link


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## XbrandonX (Nov 22, 2007)

I'm not sure how the water is here in Newmarket so I'm throwing in a 1/4 teaspoon of it in after each water change. I already dose EI and I noticed on some EI charts its listed and on others it wasn't. So I was wondering what exactly it was that it does for the water/plants.

That was my main reason for asking. Also because I wanted to create a thread with those keywords to make it easier for people when doing searches.. because when I searched I found no help regarding it


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## Rmwbrown (Jan 22, 2009)

I work on some of the contaminated fill issues in and around York-Durham so, in short, your in luck... i have the info on hand.. 

BTW: Most of the time you can get this information yourself by going to the municipalities web site and accessing their yearly water testing data. 

Anyways you have 14.145 mg/l of magnesium. Which is roughly 14 ppm. In ten gallons of water, dosing 1/4 of a teaspoon would bring it up around 17ppm.

The recommended amount for EI dosing is 5ppm. So no need to dose. Out of curiosity, why did you think M might be a limiting factor in your tank?
Magnesium is toxic in low amounts... something like 100ppm.


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## XbrandonX (Nov 22, 2007)

As mentioned it was in some EI dosing charts and I was following directions. My tanks a 45G not a 10G so at least its a little more diluted than the 17ppm you figured. I'll stop dosing it then.. this is exactly what I wanted to find out. Thanks


(toxic for who or what? Its epson salts, magnesium sulphates. I've used it in tanks of fish showing constipation in the past (potential bloat etc) It's commonly used in aquaria}


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## Will (Jul 24, 2008)

He's just saying that a 1/4 tsp (which is what you said you were dosing) would raise the magnesium about 3ppm for every 10 gallon of dilution.So in a 45 gallon tank, that 1/4 tsp you were dosing was only raising it less than 1ppm.

Naturally your tap water is about 3X higher than the level plants would want it to be- not to mean that it needs to be lowered, just that your water already has it in excess- which is the whole theory behind EI.


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## Rmwbrown (Jan 22, 2009)

Sorry Dude, my bad... I didn't back track on the post.

At 100pm it's toxic for humans.... not quite sure what happens, but I know that is fail on the municipal tests. Not sure about anything else. I'm sure your well within a safe threshold as is. I just added that for interests sake.


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## XbrandonX (Nov 22, 2007)

No, it's cool.. That's why I was asking.. I found that there was conflicting info regarding it so I wanted to check for sure. I don't want to be dosing my tank with too much of something or the wrong thing.

If I ever upgrade to RO/DI I'll resume with it.


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## Darkblade48 (Jan 28, 2008)

Rmwbrown said:


> At 100pm it's toxic for humans.... not quite sure what happens, but I know that is fail on the municipal tests. Not sure about anything else. I'm sure your well within a safe threshold as is. I just added that for interests sake.


A fail on the municipal water test does at 100 ppm does not mean that it is toxic for humans.

Magnesium sulfate solutions are sometimes used as a laxative, so that may be why higher concentrations in drinking water would receive a fail on the test.


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