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Adding Magnesium (epsom salts) to my hard water

Do you know for sure that your tap water is low on Mg? With a GH of 19, there should most likely be a fair amount of Mg present, although it is possible for it to be low. Adding Mg will increase the GH.

Dave.
 
GH is made up of calcium and magnesium.
But it could be in any ratio.

With a GH as high as yours I agree with Dave and suspect you have enough of both, but that is only an educated guess.

My tap has a lot more Mg than Ca (GH of 10) so I add calcium (in the form of gypsum).
 
Hi all,
It will add to the GH and conductivity (TDS), but not to the KH as that is a measure of the carbonate content, and "Epsom Salts" are "magnesium sulphate heptahydrate".
My tap has a lot more Mg than Ca (GH of 10) so I add calcium (in the form of gypsum).
this is an interesting one, have you got the figures for Mg & Ca? our chalk aquifer water has a huge amount of calcium but hardly any magnesium (and this would be the similar situation across most of S. England).

cheers Darrel
 
dw1305 said:
My tap has a lot more Mg than Ca (GH of 10) so I add calcium (in the form of gypsum).
this is an interesting one, have you got the figures for Mg & Ca? our chalk aquifer water has a huge amount of calcium but hardly any magnesium (and this would be the similar situation across most of S. England).

cheers Darrel

I typed my post in a hurry, I should have said that I suspect I have low Ca in my tap water.
It was an anecdotal correlation based on the fact that my balansae show calcium deficiencies (and no magnesium deficiencies) and then showed improved growth after dosing calcium.

tommyleestaples said:
So you would recommended adding Magnesium to my water? Maybe 10 ppm?

If it was me I would add some and if there was no improvement in plant growth after 3 weeks stop adding it. If you are using the EI method of regular water changes then any excess will be removed.
 
I have not planted the plants yet so maybe a good idea would be to plant the plants and see if I get any signs of magnesium defiancy then I can start adding the Magnesium (Epsom Salts)
 
tommyleestaples said:
I have not planted the plants yet so maybe a good idea would be to plant the plants and see if I get any signs of magnesium defiancy then I can start adding the Magnesium (Epsom Salts)

That would work :thumbup:
 
Hi all,
If you already have the Epsom Salts, I'd add a small amount (you only need to add 2-3 ppm), as it won't do any harm and if your water is Mg deficient it will provide enough Mg. For many terrestrial plants the problems occur when the Ca/Mg ratio becomes very large and this causes leaf chlorosis in Azaleas, Citrus etc. Magnesium is mobile within the plant which gives the instant effect in the post Rufus highlighted.
cheers Darrel
 
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