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Reverse Osmosis water - Remineralize questions.

Hi all,
@OsirisII said:
Tank is 60x45x45 so around 110l.
Click to expand...
Perfect.
The formula for "Epsom Salts" is MgSO4.7H2O and the <"RMM = 246.5">.

<"Magnesium (Mg)"> has a RAM of 24.3 and we have 1 atom of this, one of sulphur (S) (RAM = 32.1), eleven oxygen (O) atoms (RAM =16) and 14 hydrogen (H) atoms (RAM = 1).

So our RMM = 24.3 + 32.1 + (11 * 16) + (14 * 1) = 24.3 + 32.1 + 176 + 14 = 246.5 and the percentage Mg = 24.3 / 246.5 = 9.9% Mg.

I'm calling that 10%. So 1 gram of "Epsom Salts" adds 0.1g of Mg. Milligrams per litre and ppm are equivalents, there are 1000 milligrams in a gram, so we have add 100 milligrams of magnesium with each gram of "Epsom Salts" and 110 milligrams Mg with 1.1 gram.

Your tank is 110 litres, so 1.1 gram of "Epsom Salts" adds 1 ppm Mg and 11g adds ~ 10 ppm in 110 litres. You could check that with a nutrient calculator. Rotala_butterflyMg.jpg

cheers Darrel
 
dw1305 said:
Hi all,

Perfect.
The formula for "Epsom Salts" is MgSO4.7H2O and the <"RMM = 246.5">.

<"Magnesium (Mg)"> has a RAM of 24.3 and we have 1 atom of this, one of sulphur (S) (RAM = 32.1), eleven oxygen (O) atoms (RAM =16) and 14 hydrogen (H) atoms (RAM = 1).

So our RMM = 24.3 + 32.1 + (11 * 16) + (14 * 1) = 24.3 + 32.1 + 176 + 14 = 246.5 and the percentage Mg = 24.3 / 246.5 = 9.9% Mg.

I'm calling that 10%. So 1 gram of "Epsom Salts" adds 0.1g of Mg. Milligrams per litre and ppm are equivalents, there are 1000 milligrams in a gram, so we have add 100 milligrams of magnesium with each gram of "Epsom Salts" and 110 milligrams Mg with 1.1 gram.

Your tank is 110 litres, so 1.1 gram of "Epsom Salts" adds 1 ppm Mg and 11g adds ~ 10 ppm in 110 litres. You could check that with a nutrient calculator. View attachment 203342

cheers Darrel
Click to expand...
Ok i will add 11g of this in next waterchange.
@John q thank you also.
I think that 6g is lean dose and 11g is full dose?
 
@OsirisII Both methods will work, people just have different views about things. My 3g per water change was targeting a constant 5ppm in the water column, used to re mineralise the incoming water.
Darrels approach is to target 10ppm p/week in the fertiliser scence, with accumulation that will lead to about 20ppm the water column.

I'm not sure 20 ppm is needed, but it will work.
 
John q said:
@OsirisII Both methods will work, people just have different views about things. My 3g per water change was targeting a constant 5ppm in the water column, used to re mineralise the incoming water.
Darrels approach is to target 10ppm p/week in the fertiliser scence, with accumulation that will lead to about 20ppm the water column.

I'm not sure 20 ppm is needed, but it will work.
Click to expand...
Ok I am not sure about that 11g then because I use Tropica Specialized, and it contains Mg already. I use 1ml daily
Units are some w/w%
1680101752538.png
 
Hi all,
OsirisII said:
Ok i will add 11g of this in next waterchange.
@John q thank you also.
I think that 6g is lean dose and 11g is full dose?
Click to expand...
@John q "1/2 a teaspoon" in your 55 litre water change should be plenty. I used 10 ppm, because it makes the maths easier. I'm not too hung up on ratios, optimal growth etc. and I just need the plants to have some magnesium.
John q said:
Darrels approach is to target 10ppm p/week in the fertiliser scence, with accumulation that will lead to about 20ppm the water column.

I'm not sure 20 ppm is needed, but it will work.
Click to expand...
Yes, minus what the plants take up. This <"isn't easy to measure">, but I'm not going to attempt to.

I'll be honest <"my approach to all fertilisers"> is pretty ad. hoc. and I don't add them on a routine basis or <"weigh them out accurately"> etc.

I'm lean dosing, but using the growth and leaf colour of Amazon Frogbit (Limnobium laevigatum) as an <"indication of fertiliser level">.
OsirisII said:
because I use Tropica Specialized, and it contains Mg already.
Click to expand...
Just add John's "half a teaspoonful" (or a whole teaspoonful) and see what happens.

cheers Darrel
 
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Myself, darrel and many others will always try and help, that's what the forum is all about.

Get your head around the Magnesium and then you probably need to address the lack of potassium issue. I'll leave that to others who have experience in growing plants in hard water, I don't, so can't advise on that.
Don't forget to take note of the comments and questions by @Kalum and @Geoffrey Rea they are worth their weight in gold 😀
 
You probably won't have at the minute because you've been dosing equilibrium which is loaded with potassium. I'm not sure how well aqua soil retains potassium but I do know the ferts you dose add about 0.65 ppm of K per week, so potentially this might not be enough.

I'm unsure if lean dosing will work in hard water, others with experience of this will have to offer advice on this subject.
 
John q said:
You probably won't have at the minute because you've been dosing equilibrium which is loaded with potassium. I'm not sure how well aqua soil retains potassium but I do know the ferts you dose add about 0.65 ppm of K per week, so potentially this might not be enough.

I'm unsure if lean dosing will work in hard water, others with experience of this will have to offer advice on this subject.
Click to expand...
Sometimes I really wish I went full monkeys and bought all ADA ferts. Atleast there I would have room to move. Still have like 4 liters of this tropica 😪
 
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