# Magnesium



## Wasserpest (Jun 12, 2003)

No and no. Although they might get some Ca and Mg from the substrate, but then levels are not 0.

Often it is possible to get your water data report which should give you an idea of the Ca:Mg ratio in your water.

If plants react positively after adding Mg, well... keep adding. :thumbsup:


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## Hoppy (Dec 24, 2005)

Adding some magnesium, Epsom Salts, isn't going to do any harm to either fish or plants, and it might help the plants, so why not dose it along with the trace element mix. Just as CSM has had Boron added to make it a more complete trace mix, and some people add more iron to make it still better, I add a dose equal to the dose of CSM+B when I dose traces. That is very little Magnesium, but I would rather have some than almost none.


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## happi (Dec 18, 2009)

[Just report please]

spam ?


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## Hoppy (Dec 24, 2005)

happi said:


> [Just report please]
> 
> spam ?


Say what? Is this a mistake post or does it mean something?


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## sewingalot (Oct 12, 2008)

There was spam in the thread that was removed.


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## barbarossa4122 (Jan 16, 2010)

I dose about 1ppm of Mg 3 times/week for a total of 3ppm/week.


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## Diana (Jan 14, 2010)

Plants need over a dozen elements to grow. 
Some they need in very large amounts:
H, O, C, N, P, K. 
H and O are water, and are not thought of as fertilizers. 
N, P and K are 'macros'. They are the true fertilizers (there is a legal definition of fertilizer, and that is it: contains N, P, or K at a certain minimal level)
C is the other 'macro' that we often need to help out the under water plants with. 

All the others are needed in smaller amounts. Even though they are needed at lower levels plants cannot live if any of them are at 0 levels. These are grouped as 'micros'
Here is a partial list:
Ca, Mg, Fe, S are used in somewhat larger amounts than the rest of the micros. Maybe these need another name because they are used at intermediate levels. 
B, Mn, Zn, Cu, Se, Mo are used in smaller amounts. These may be toxic if they are present in larger amounts. 

If any of these are absolutely not there (laboratory conditions can create a zero level of something) then the plant dies. 

In a home aquarium there are many sources of these nutrients, and a true zero level is not likely to occur. But lower than optimum levels do happen, and the plants do not die, but show various symptoms of deficiency such as curled leaves, poor color, poor growth and other symptoms. Plants can make up for deficiencies in several ways. One of these ways is to move minerals around within the plant. Taking nutrients out of the older leaves and using them to make new leaves. 

If one nutrient is present in excessive amounts it can block the plants' uptake of something else. Then the plant shows a deficiency, even if that element is present in the tank. One example: if levels of Mn, Zn or Cu are too high plants cannot take in as much Fe as they need, even if the Fe is present. Plants will show Fe deficiency. 

Fish food has all the elements needed to grow plants. This is what a low tech tank depends on. But we do not want to add that much fish food to a high tech tank. 
Tap water can hold many minerals, and is another source for aquarium plants. It is a variable source, though. You need to get a report on your own tap water and see what is present, and at what levels to get a feel for how much you can count on water changes to be a supply of nutrients for the tank. 
A rich substrate may supply a lot of minerals to the plants, but eventually it will get exhausted if these minerals are not replaced. 

Specifically Ca and Mg:

Most plants use Ca and Mg in a ratio that is not too far off of 4:1, Ca:Mg. 
If the GH in the tap water is over 3 degrees there may be enough of each. A separate test for each is the only way to be sure of these levels. 
If the GH in the tap water is less than 3 degrees then it is more likely that one or the other is lacking. Again, test for Ca and Mg separately to be sure what each level is. 
If you are using RO or DI water, then there is so little of any mineral that the water will need to be remineralized before using it for the aquarium. The exact amount of minerals to add depends on the sort of tank you are running. 

If you start with RO water, and add only Epsom salt the GH test may show that the GH is OK. However, Epsom salt is just Mg; there is no Ca. All the other minerals are still missing, too. This sort of remineralizing of RO water is not the right way to do it. You are not just looking for a particular color on your GH test. You are trying to add the right amount of each mineral to make the water right for fish and plants. There are combined products that are blended with the correct ratios of several minerals that are right for the plants and fish. By using one of these products at the right dosing you are more likely to get a better blend of minerals, in the right ratios. These products usually contain Ca, Mg, K and often Fe and other micros, often in the sulfate form, so they also contain S. The lesser micros may be in there, or may not. You will still get the right color on your GH test, and if you test for many other minerals they also will show the right colors. Even better, the fish and plants will respond by growing and thriving when all the minerals they need are present in the correct levels.


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