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still trying to get my head around dry fert amounts.

john6

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23 Mar 2022
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179
Location
Scunthorpe
My head is starting to hurt after trying to learn how much NPK i should be adding to my tank daily, there are so many different views, anyway i think i have come up with what i need.
N 12ppm per week
P 4ppm per week
K 18ppm per week
Mg 6ppm per week
My tank is i would say med-high planted with just a sand substrate.
Do you think that is enough to start with and just tweak things if i have to or am i way off?
I'm not interested in exacts amounts but more of a target range
 

Zeus.

Fertz Calc Meister
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1 Oct 2016
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Yorkshire,UK
Much depends on which regime you are after using.
Most ferts for gardeners and farmers use NPK targets, whilst many of us use NO3, PO4 and K targets in the hobby but not exclusively.
The IFC you have had a little play with has many popular fert regimes and uses NO3 and PO4 targets, but does give the NPK valves in the results table also.
The IFC also gives the dry dosing weights for you tank as well as the mass of salts to add to make a solution. The choice is yours.
 

Zeus.

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Just did some goal seek on the IFC calculator to find out what a 12 ppm N and 4 ppm P would yield
1650303480751.png

So
12ppm N = 53.1ppm NO3
4 ppm P = 12.3 ppm PO4
Which both are in excess of EI dosing, so there will be no shortage of N and P
 

MichaelJ

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9 Feb 2021
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1,690
Location
Minnesota, USA
My head is starting to hurt after trying to learn how much NPK i should be adding to my tank daily, there are so many different views, anyway i think i have come up with what i need.
N 12ppm per week
P 4ppm per week
K 18ppm per week
Mg 6ppm per week
My tank is i would say med-high planted with just a sand substrate.
Do you think that is enough to start with and just tweak things if i have to or am i way off?
I'm not interested in exacts amounts but more of a target range

Hi @john6,

What @Zeus. says. Those are very high levels of N and P - the Mg and K levels are fine though.

What compounds are you using for N and P dosing?

Cheers,
Michael
 

plantnoobdude

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17 Mar 2021
Messages
841
Location
uk
I think John6 is getting confused between N and No3, and P and Po4.

the conversion from N to No3 is multiplying N by ~4.5!
the difference is N has 3 oxygen!

P to Po4 is multiplying by ~3.
most people report their dosing by no3, po4, K targets. which is quite confusing because many people list them as N, P and K.
 
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Zeus.

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Yorkshire,UK
most people report their dosing by no3, po4, K targets. which is quite confusing because many people list them as N, P and K.
Which is why I prefer quoting NO3 and PO4, as then there is no doubt ;)
 

john6

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23 Mar 2022
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179
Location
Scunthorpe
I started out using kno3 and kh2po4 for no3 and po4, but then i got a water report and my water no3 is 20 and po4 is 1.94.
So i am wondering if my original 'targets' were off, so have decided to just dose mag sulphate and pot sulphate, there are so many different views on what the range of any given fert should be, it reminds me of when i first started reefing.
 

Zeus.

Fertz Calc Meister
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1 Oct 2016
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4,604
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Yorkshire,UK
I started out using kno3 and kh2po4 for no3 and po4, but then i got a water report and my water no3 is 20 and po4 is 1.94.
So technically you shouldn't need to dose any NO3 or PO4 'if' your water report is correct. Thats the 'crocks of it' and there is only one way to find out 'try it' plus with those levels of N and P odds are there will be plenty of Potassium (K) in their also, @LondonDragon does have a tank that he doesn't dose any ferts and it still does well, a little Mg is worth adding (one teaspoon Epsom salts per 100l adds about 5ppm Mg) IMO as cheap and most of UK is low in Mg.
 
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LondonDragon

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21 Feb 2008
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London
Your values are similar to mine: have a look HERE and take a look at my latest photos, if you have similar plants should be fine!

@LondonDragon does have a tank that he does dose any ferts and it still does well
The tank in question is mentioned HERE (It's a rollercoaster thread that one!)
 
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