MgSO4 to MgSO4*7(H2O) (Starting to use EI)

[André Inácio]

Hi all,

I've recently started a new planted tank project, mainly to learn about EI and plants needings.
I've bought the EI Starter Kit (from AquariumPlantFood), and made the recipe according to them.

4tsp Potassium Nitrate
1tsp Potassium Phosphate
6tsp Magnesium Sulphate
500ml Water

Although, I would like to know more precisely how many ppm's am I adding to my tank.

I've been trying to use EI calculators (http://www.theaquatools.com/fertilization-calculator), but all of them ask for MgSO4*7(H2O) instead of MgSO4, (witch is what I bought from AquariumPlantFood). I know that MgSO4 and MgSO4*7(H2O) aren't the same thing, so the calculator results will be wrong, so what I would like to know is: is there anyway to know for example, how many grams of MgSO4 corresponds to 100grams of MgSO4*7(H2O)?

Hope this makes sense, and sorry for my bad english.

Thanks in advance

André

 

[ian_m]

Most of the magnesium sulphate you buy will be hydrated form of MgSO4.7H2O and in the form of crystals.

http://en.wikipedia.org/wiki/Magnesium_sulphate

 

[ceg4048]

Although, I would like to know more precisely how many ppm's am I adding to my tank.

This is the birth of a very bad habit, which will never help you grow better plants and will bend you mind in the wrong direction.

There is a very good reason that the dosing scheme is called The Estimative Index and not The Precision Index.

Cheers,

 

[Crossocheilus]

With Ei all you are trying to do is provide more ppm of nutrients than the plants could ever need. As long as you are providing enough it doesn't really matter. It is very difficult to overdose.

See this article written by ceg4048:

http://www.ukaps.org/index.php?page=dosing-with-dry-salts

I would recommend just choosing a calculator and then stick with that.

 

[André Inácio]

Thank you all for the replies.
Yes, I am well aware that the Estimative Index base is exactly the word "Estimative", and I am getting good results with the recipe provided by AquariumPlantFood, my tank has almost two months, and plants are growing good 🙂 Some algae problems but i think i am getting rid of them. But, anyway, I would like to know if there is a way to know how much 100gr of MgSO4 corresponds to MgSO4*7(H2O), since I have no quimic knowledge, and i think that knowledge is never in excess 🙂

 

[GlassWalker]

The magnesium sulphate from APF is in heptahydrate form so no conversion required in this case. I had asked the same question a while back as I wanted to use it to dose a marine tank also where EI is not applicable. Actually, it looks like the APF website has been updated since the last time I looked and the magnesium sulphate page now explicitly states it.
http://www.aquariumplantfood.co.uk/fertilisers/dry-chemicals/dry-salts/magnesium-sulphate.html

 

[André Inácio]

Thank you! Exactly, when i ordered my salts it was only MgSO4, but now I see heptahydrate too. Everything is much more simple now, no conversions required 🙂