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Discussion Starter · #1 ·
I will be making three separate stock solutions for NO3, PO4 and K. Each will be 500ml with a dosing requirement of 20 ml to achieve the desired ppm.
For convenience, I would like to combine all three stock solutions . If so, to maintain the same individual ppm per fertiliser, do I add 20ml or 60ml into my tank?
Regards
LAKA
 

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If you tell me the concentrations(ppm) of each that you are trying to reach I can help you figure out a mixture that will work.
 

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You still add 20ml. The ppm does not change if you add something else. For example, If you have 10ppm of sugar in a solution, adding salt to 10ppm never changes the sugar level. They're both independent.

Btw, you'll most likely not need to use additional potassium. KNO3 generally has enough K in addition to NO3.
 

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Discussion Starter · #5 ·
Thank you very much for the answers.
As I suspected, combining all three solutions to make 1500ml will require a 60ml dose.i doubt I can place all three ferts in 500ml stock solution and dose per 20ml because the compounds will probably not fully dissolve and will form a sediment.
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LAKA
 

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Thank you very much for the answers.
As I suspected, combining all three solutions to make 1500ml will require a 60ml dose.i doubt I can place all three ferts in 500ml stock solution and dose per 20ml because the compounds will probably not fully dissolve and will form a sediment.
Regards
LAKA
That would depend on what size tank you are dosing and what the ppm you are shooting for. On a 10g tank and shooting for EI levels 20mls should not be a problem.
 

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If you're mixing equal parts of all 3 for a total of 1500ml you need to dose 60ml.
This is incorrect.

You still add 20ml. The ppm does not change if you add something else. For example, If you have 10ppm of sugar in a solution, adding salt to 10ppm never changes the sugar level. They're both independent.
This is correct.

Thank you very much for the answers.
As I suspected, combining all three solutions to make 1500ml will require a 60ml dose.
This is incorrect.
 

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Discussion Starter · #8 ·
Now you have really confused me.

My interpretation of Zorfox's thread is that salt (compound B)in his example is added as a DRY WEIGHT into the stock sln containing sugar (compound A). In that case , the stock volume remains the same. I agree 20 ml dose let's say of compound A will still give the same ppm irrespective of the addition of compound B or C Or D all or three combined, since the volume of stock solution remains unchanged.

If on the other hand I double the volume of stock solution using distilled or RO water, then I would need to double the dosage say of compound A to achieve the same ppm. Half the volume, half the dosage to maintain same ppm. Common sense.

So why would the dosage of compound A remain the same if I double the stock sln containing compound B or C or D?

LAKA
 

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My post was in response to your original question as was Darklblade's. If you increase the volume of water and keep the fertilizer addition the same, yes you increase the dose to yield the same ppm.

Example,

All of these provide the same PPM per dose...

1 tsp. of sugar in 500ml dose = 5ml
1 tsp. of sugar in 1,000ml dose = 10ml
2 tsp. of sugar in 1,000ml dose = 5ml

Sorry for the confusion.
 

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I figure these just a bit differently, but get the same results, the same concept:

1) Figure out how much fertilizer all my tanks will use in one week.
2) Figure out how much volume I want to dose each day. For me, I need a way to quickly figure out how to dose many different sized tanks. I choose to dose @ 1ml per 3 gallons of tank volume.

This means I can walk up to each tank with a syringe in hand and think "OK, 15 gallon tank, squirt in 5 ml.... OK, 45 gallon tank, squirt in 15 ml... OK 10 gallon tank, squirt in 3 ml" and so on.

3) Multiply out all that I need to dose all my tanks for a week comes out to 1000 ml. I actually mix up 2 weeks worth at a time, so I make 2 liters of Macros and 2 liters of Micros.
a) I add the 2 weeks worth of KNO3, KH2PO4 and K2SO4 to the Macros bottle, and CSM+B and chelated Iron to the Micros bottle.
b) Add Excel to both bottles. So, when I dose any fertilizer the tank is also getting the daily dose of Excel.
c) Top off with distilled water.

The actual amounts of each fertilizer have changed as I change my maintenance schedule and the livestock level in the tanks. But even when I have to add the highest level of fertilizers the amounts are easily dissolved in the water.

I have adjusted the dosing levels, too. For a while I was dosing 1ml of mix per 1 gallon of tank volume. Then I tripled the concentration of ferts, so cut the dosing to 1/3 as much.
 
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