re k2so4

[M0rph3us]

hi all just bought k2so4 from Dr Mallick.. im now thinking how to make the solution.. can i use the calculator from http://www.csd.net/~cgadd/aqua/art_p...osage_calc.htm
or shld i follow the instructions on the bottle?
and also how many times a week do i dose?

[vinz]

Use the calculator. Dose 20 to 30ppm once a week.

[Vican]

So, for a 500l tank , I should be dosing 4 teaspoons of K2SO4 and equivalent amount of MgSO4 if I add it directly to the tank?

[vinz]

Don't add directly.

I use 6 teaspoons of K2SO4 for my 6 ft tank to get approx 30ppm. It's been sometime since I added Mg.

[Vican]

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On 12/19/2002 12:31:37 AM

Don't add directly.

I use 6 teaspoons of K2SO4 for my 6 ft tank to get approx 30ppm. It's been sometime since I added Mg.
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Why can't I add directly? It dissolves in 1/2 hr max right?

[vinz]

Just a guideline I follow when adding stuff like that, to be on the safe side. Dissolves better during pre-mix. Dumb fishes/shrimps don't try to eat it.

[Simon]

yup, I too just mix with some water and pour it in...

[tawauboy]

what do you use to measure 1 teaspoon?
those measuring spoons used for baking measurements?

[Allen_1971]

Tawauboy,

Thats what I use... I have them in sizes ranging from 1/2 tsp to 1 tbsp in incremental steps.

Vican,

As for adding MgSO4, you definitely do not want to add it in the same quantities as K2SO4. You will rocket your sulphate levels. K2SO4 is 45%K and 55% SO4... MgSO4 is 20% Mg 80%SO4. Also Mg is needed in lower levels than K, so use sparingly.

[vinz]

Same as Allen, I use the bunch of spoons sold for baking and cooking needs. Also a measuring cup, and a strainer (for breaking up large clumps).

[jacian]

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On 12/19/2002 1:34:48 PM

MgSO4 is 20% Mg 80%SO4.
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Espom Salts are fully hydrated magnesium sulfate which is MgSO4-7H2O, thus it is approx. 9.7% Mg and 39% SO4.

[M0rph3us]

if the MgSO4 is from Dr Mallick it says 13% Sulpur 9% Mg

[Allen_1971]

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On 12/19/2002 2:00:21 PM

Espom Salts are fully hydrated magnesium sulfate which is MgSO4-7H2O, thus it is approx. 9.7% Mg and 39% SO4.

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Really? Thanks, I didn't know that... OK that changes the % a bit... though when I calculate it works out to 9%Mg and 35%SO4... mebbe I made a mistake. Anyway, my main point being that the ratio of Mg to SO4 is 1:4 in contrast to K2SO4 which is almost 1:1. So while raising our K by 10 ppm results in a roughly 10ppm SO4 increase, 10ppm Mg boost results in a roughly 40ppm SO4 boost.

p/s Just to clarify, Can I rephrase the Epsom Salts to MgSO4-7(H2O)? In other words the molecular weight is MgSO4 plus 7 molecules of water? Also after playing around with the calculations, your percentages and also those given from Singapore hydroponics seems to tally more with MgSO4-6H2O? Which is correct?

[jacian]

My cal. as such
Mg : 24
S : 32
O : 16
H : 1

MgSO4.7(H20) = 24 + 32 + 4(16) + 7 (2 + 16)
= 246.

% of Mg = 24/246 x 100% = 9.7%
% of SO4 = 96/246 x 100% = 39%

[Allen_1971]

ok cool thanks... found the mistake on my spreadsheet... was referencing the wrong cell... Mg is 9.86%, SO4 is 38.98% and S alone is 13.01%