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Fert Calculator V1.8 - New version out! Check Note first/last post!

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Hi all,
madhunm said:
Lets say I am using RO/DI water with a 0 TDS reading. .........What ratio of N-P-K-Ca-Mg-Fe would you suggest?
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If I was starting from a blank slate I'd try a few commercial mixes (like you've done on your spreadsheet) to find one that gives me good plant growth and just replicate ("Clone") that. Have a look at <"it's very green....">.

It doesn't matter where an ion has come from, every K+ ion is the same as every other K+ ion when it is in solution.

The issue for a lot of people is that their water is hard, with a lot of calcium (Ca) and carbonate buffering present, which means that they have <"to add a lot of the other cations"> to achieve the optimal ratio.

In the hard water scenario I would take <"the path of least resistance"> and grow plants/keep fish that are happy in hard water.

cheers Darrel
 
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madhunm said:
My observation is that for setups that have low to medium lighting, K is usually higher than N.

Regards.
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Have just been though the compare list on the lastest Calculator and only one regime/commercial fert had a significant higher K dose than NO3 dose and thats ADA dosing.

I did excluded the commercial fert that didnt have any NO3

madhunm said:
Also, these are percents... not PPM.

For example,

2.66% N is about 5.89PPM
10.75% K is about 4.47PPM

Regards.
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Need to also read the analysis label carefully on the commercial ferts as thay will always try to add another layer of 'mystic confusion'

So will quote say the '4.23K w/w%*' and at the bottom of the label say '* K2O has been used as source of K' so you have to do the little extra calculation to convert the K2Ow/w% into K w/w% first before converting to K ppm, which happens to be slightly less than K2O ppm.

Quoting 'w/w%' is just a way the commercial fert companies get round the law, they quote the analysis as they have too by law, but the law doesnt say what units they have to use, so using these units does not make life easy for anyone.

If they quoted the analysis in ppms and elements/compound we all use it would be easy. It would be even better if they gave the ppm yield per dose per tank size, open honest and transparent will all the information.

There is only one commercial fert 'that I am aware off' that does this is APT Complete by D Wong

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But Dennis Wong has alway been a great source of information and open and transparent in his explanations, always trying to present the information is an easy to understand format

His fert doesnt quote NO3 as it will be a urea compound hes using (cheapest) and quoting 'NO3' would be false as its the bacteria in the tank that convert the Urea into NO3 for the plants. But quoting K2O w/w% is just misdirection as once K2O is in solution it forms 'K+' ions

Just comparing his K to N ration K>N however you need to convert the N to NO3 and account for the dose 😵 havent added APT complete yet, however going off the rest

1594449402949.png

I would of estimated that '1.5ppm N' yields '6.64 ppm NO3' once the bacteria convert it will be higher than the 4.0 ppm K
 
Well, FWIW, here are some labels that I made for my bottles
 

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Hi all,
madhunm said:
When you are entering the tank volume, do you enter the tank volume and sump volume together?
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Yes add them together. It is the total volume of water in the system that you are interested in. You need to take a bit off for glass thickness, volume of substrate, volume of filter media etc.
Zeus. said:
So will quote say the '4.23K w/w%*' and at the bottom of the label say '* K2O has been used as source of K' so you have to do the little extra calculation to convert the K2Ow/w% into K w/w% first before converting to K ppm, which happens to be slightly less than K2O ppm.
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I couldn't agree more, it would be <"so much easier if everything quoted % of the element"> and then there are also the <"different units of hardness">, not very helpful.

At work I'm trying to get every one to use <"scientific notation for the orders of magnitude"> so mg/L (mg L-1) rather than ppm etc.

cheers Darrel
 
You could do, but to be honest all it will change is the amount of salts you add, but your sump has no plants so it doesn't really matter esp for NPK and micro ferts, if your plants are healthy the ppm are irrelevant. As for remineralising clones V1.8 doesn't do it very well, think I pulled it from the download.
V1.9 is so more refined it's at another level all together. However as it is it is completely non user friendly ATM. Only two people could make sense of it as it is .
We have no idea when it will be ready for even pre- release which will only be with a few testers we have on our list.
The aim on release is it will need no/little support from us, it will be self explanatory and user friendly for both experts and folks new to the hobby.
 
I have a question regarding the solubility of K2SO4.

I tried to dissolve 18g of this in 200ml of water; it doesnt want to. When shaken vigorously, it goes into suspension and then after a while, settles on the bottom.

Is this normal?

Regards.
 
Hanuman said:
1. You didn't use RO water
2. You have rather low grade K2SO4
3. You are sub 10 degrees celsius

Try warming it up see if it fully dissolves.
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I did use RO water
I can't speak to the grade; I picked it up from an agro chemical company
I'm definitely not under 25°C 🙂

I haven't heated it yet... But, so far, shaking the bottle is kinda sorta working. 🙂
 
Hi all,
Hanuman said:
Try warming it up see if it fully dissolves.
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madhunm said:
But, so far, shaking the bottle is kinda sorta working
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That should work.
madhunm said:
I tried to dissolve 18g of this in 200ml of water; it doesnt want to
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Are there any other salts in the solution? You can only dissolve 111g/L of K2SO4 if there aren't any other salts in solution, the solution is fully saturated at that point. If you try and add another salt, even a really soluble one, the K2SO4 will just come back out of solution.

cheers Darrel
 
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