Will APFUK starter kit suit my needs??

EA James

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Hi all,

During lockdown i bought my first lot of dry salts, individually from Aqua plants care. Since then I've had a few minor issues caused by excess nutrients and from posts on here a few people thought my nitrates were high enough from the tap to not need to add any more.

I Haven't been dosing for around a month now and surprisingly the diatom looking algae has cleared up and the glass is staying clean in between water changes. I'm also injecting co2 so i'm quite shocked that i'm not having any issues.....BUT!... I know that its probably not going to stay like that?! Saying that I'm starting to see a bit of a difference in some of the leaves of my crypts (yellow dots) but I'm not sure on what that is but generally the tanks doing ok.

So according to my water report my minimum nitrate level is 31.6 and i think the max was around 40ppm. I was using potassium nitrate in my old recipe so firstly does the APFUK starter contain that and if so should i not add any? Or should i swap the KNO3 for something else?

Also on that note how long would it take for the nitrates in my tank to deplete? I'm guessing plant volume would play a big part in that answer so probably a stupid question?!

I'll post a pic of the tank in it's current condition so you can see the plant mass for the fert help, as always, any help will be appreciated 👍

Cheers, James
 

EA James

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X3NiTH

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APFUK salts totally fine to use.

If there is a commensurate amount of Potassium to Nitrogen in the tap water then omit the KNO3 from your dosing regime, if there’s not then you can supplement Potassium from either Potassium Chloride or Potassium Sulphate, the Carbonate or Bicarbonate of Potassium if used will increase the KH (Carbonate Hardness) of the tank water and pH will rise correspondingly.

If you are using Magnesium Sulphate as part of your macro mix (it comes in the APFUK kit along with KNO3) then I would suggest sourcing and using Potassium Chloride for the Potassium rather than the Sulphate if only to limit the total amount of Sulphate in the tank.

There’s not many limits to what you can do, nothing stopping you getting creative and using all the forms of Potassium together if you need to get specific values for everything in the water.

:)
 

EA James

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Hi @X3NiTH sorry i haven't had the time to reply to you sooner. Thank you for the reply

If there is a commensurate amount of Potassium to Nitrogen in the tap water
I don't that I'm afraid, I'm still very new the whole EI thing and science wasn't my strong point at school and still isn't now so to be honest i find it all a bit confusing! Do i need a Potassium test kit to help find the answer?

nothing stopping you getting creative
Apart from lack of knowledge 😂 I'm trying to get it to sink in so please bare with me!

Thanks again
 

dw1305

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Hi all,
Do i need a Potassium test kit to help find the answer?
No, you don't. There <"is a kit">, but it is actually quite difficult to measure <"potassium (K) levels colormetrically">, because of the <"solubility of potassium salts">.

Measurement is very straightforward with any of <"Flame Photometry, Atomic Absorption Spectrophotometry (AAS) or Inductively Coupled Plasma (ICP)"> if you have access to them.

Your water company has the right analytical kit, but there isn't a regulatory limit for potassium, so most companies don't report the value.

If you have high levels of nitrate (NO3-) in your tap water, you are also likely to have elevated levels of potassium from the same sources.

If you thought you might have low potassium levels and you didn't want to add any potassium nitrate (KNO3), then @X3NiTH's is a good suggestion
I would suggest sourcing and using potassium chloride
KCl is easy to find as "sodium free salt".

cheers Darrel
 

X3NiTH

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Natural background Potassium levels worldwide in drinking water supplies is usually somewhere between 1ppm to 5ppm, there are outliers to this of course depending on local mineralogy and agricultural pollution. Here’s what the WHO have to say about background potassium - Potassium– Background Document Revised WHO draft – March 2009

If you assume you have low levels then you can add a Potassium source to a commensurate level to that of the Nitrate and be a near or not far over 1:1 ratio of N:K if there is already 1:1 of N:K without a further salt addition then adding more is ok, a ratio of N:K where 1:>2 is not problematical, I have run 1:>5 (sourced from Potassium Bicarbonate for KH dosing) and I never saw any issue.

Add whatever is easiest!

:)
 

EA James

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If you have high levels of nitrate (NO3-) in your tap water
Minimum 31.6
Mean 35.5
Max 40.5
I'm guessing I'd work off the middle figure? Is that an adequate amount for my tank for the week?

If you assume you have low levels then you can add a Potassium source to a commensurate level to that of the Nitrate
Well from looking at potassium deficiencies on good old google today i think a few of my plants may be suffering with this. But, I haven't been dosing any ferts for about 5/6 weeks now so that could be why, not sure if they were there before. I'll take your advice and get some potassium chloride, i then use that instead of the potassium nitrate in my mix?

Thanks guys :)
 

dw1305

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Hi all,
Minimum 31.6
Mean 35.5
Max 40.5
I'm guessing I'd work off the middle figure? Is that an adequate amount for my tank for the week?
Yes, that should be plenty of NO3, even the minimum value (which will be sometime in the winter) is pretty high.
I'll take your advice and get some potassium chloride, i then use that instead of the potassium nitrate in my mix?
Yes. There is a slight difference in the % percentage pf potassium, the RAM of K is 39.1 and the RMM of KNO3 is 101 and it is 36% K. For KCl the RMM is 74.5 and it is 39.1/74.5 = 52.5% potassium.

This means that there is the same amount of potassium in 1g of KNO3 and ~0.7g of KCl.
i think a few of my plants may be suffering with this. But, I haven't been dosing any ferts for about 5/6 weeks now so that could be why,
You should get a pretty instant greening if your plants are potassium deficient. For geological reasons your tap water won't have supplied much magnesium (Mg) either, so that is another possibility for the deficiency symptoms.

cheers Darrel
 

EA James

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Thanks for the reply @dw1305 thats helped things be more clearer in my head!
These are the few deficiencies I’ve noticed and from what I’ve read online they do seem to be caused by lack of potassium and/or magnesium, would you agree?
Cheers, James
 
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