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PMDD, chemistry, mixing and dosing...

Hello, I tried to send out this email to the list before, but apparently it never got there... Hopefully this one does and it is not repeated...

There were a lot of chemistry topics butted about recently, and most had very good answers from very knowledgeable people. My chemistry is quite rusty, so I was hoping if someone could help me with this PMDD problem.

Firstly, I must tell you that instead of PMDD, I am trying to use this hydroponic nutrient powder. This is because I can get all the ingredients for PMDD except potassium nitrate. So far all my attempts to find a substitute for potassium nitrate (calcium nitrate, magnesium nitrate) have failed, as they increase the hardness of the water too much.

In addition, the trace element mix that i have tried to use in the past has a high concentration of copper, and a low concentration of iron... Not exactly suitable, especially dosed daily as I take it the copper will accumulate over time...

Anyway, this 'hydroponic nutrient powder with trace elements' has all the ingredients of PMDD, and in more reasonable amounts (I think)... Here is its chemical composition:

total Nitrogen 7.6 %W/W
total P 3.1
total K 18.2
S 4.5
Mg 3.5
Fe (as chelate) 0.34
Mn 0.08
Zn 0.04
Cu 0.03
B 0.003
Mo 0.001

Now I know the iron concentration is low, but I also have this chelated iron powder which consists of:

12.0% Na Fe EDTA

My question is, and hopefully someone can help me out here;)... Can I use this hydroponic mix in the aquarium, my concern is that not enough nitrogen is provided proportionate to the trace elements... Also, can I add the iron chelate (and if so, how much?) to the mix to boost the iron levels?

Since this is already all in one mix, can anyone tell me how much powder and water to mix, and then a rough guide on how much to dose daily? This is because my test kits on nitrate are not very accurate, and always read zero... I have a high light heavily planted tank, with CO2. 

If anyone could help me with this it would be an IMMENSE help:) Thanks in advance!

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