DYI fertilizer & DYI RO re-mineralizer

[arcturus]

I am planning to start preparing a DYI fertilizer, likely a clone of the "APFUK EI start kit" or "EI mid" since I am using a significant amount of Tropica aquasoil. I can also try the "EI full" if that is a good option for a tank with (new) subtsrate and aquasoil. This is a ~250l tank with CO2 injection. Sadly, I will be forced to start using RO water in a few weeks since a water softener (using sodium chloride) was installed in our condominium. This means I will also need to re-mineralize the RO water after the weekly water changes.

The goal is to prepare a liquid macro "all in one" solution since I have a dosing pump. For now, I will continue using a commercial micro liquid fertilizer with chelated iron. In terms of macro salts, I can get hold of the following:

• Potassium Phosphate (KH2PO4)
• Potassium Sulfate (K2SO4)
• Magnesium Nitrate Hexahydrate (MgN2O6-6H2O)
• Note: there is no way to get Potassium Nitrate around here.

I am using the ICF calculator to get the correct dosages. My questions are the following:

• Do I need to adjust the amount of Magnesium Nitrate since the calculator does not seem to have the Hexahydrate version (MgN2O6-6H2O)? Or the Hexahydrate has no significant impact on the numbers?
• I am planning to dose ~30 ml daily. So, 1 liter of the macro solution will last ~4 weeks. Should I add a stabilizer to the solution? If yes, what exactly will I need to add? I have seen a dozen different answers to this question...

Regarding the RO re-mineralizer. I was advised to use <this one> and to raise GH to 6° and KH to 3° (conductance of ~300µS). Could anyone give me some tips on how to produce a DYI re-mineralizer with a similar GH:KH ratio and a suitable Mg:Ca ratio?

• Which salts do I need for the re-mineralization? Or is it preferable to use a commercial re-mineralizer?
• Is there any chemical interaction I need to be aware of between the re-mineralizer salts and the macro salts?

Many thanks for any suggestions!

 

[dw1305]

Hi all,

Do I need to adjust the amount of Magnesium Nitrate since the calculator does not seem to have the Hexahydrate version (MgN2O6-6H2O)? Or the Hexahydrate has no significant impact on the numbers?

It will always be the hexahydrate in use, just because magnesium nitrate is hygroscopic and Mg(NO3)2.6H2O is the stable hydrated form. The only way you could keep it in its anhydrous form would be to heat it and then keep it in a desiccator until use.

In terms of the magnesium (Mg) and nitrate (NO3) content the water of crystallization makes quite a difference. The RMM of Mg(NO3)2 is 148.3 and Mg(NO3)2.6H2O = 256.4. The 108 difference is 6 oxygen (O) RAM 16 + 12 hydrogen (H) (12).

This means that you would need to add 17.3g of the hexahydrate to give you as much NO3- and Mg++ as 10g of anhydrous Mg(NO3)2.

cheers Darrel

 

[dw1305]

Hi all,

Could anyone give me some tips on how to produce a DYI re-mineralizer with a similar GH:KH ratio and a suitable Mg:Ca ratio?

You don't need to add any magnesium (Mg), because you've already added it with your magnesium nitrate, so you could just use calcium chloride (CaCl2.6H2O) and potassium bicarbonate (KHCO3) to give you a 2 : 1 ratio of dGH : dKH.

1 dGH = 7.2mg/l Ca++. The workings for dGH and dKH are in this post <"Do I need GH/KH"> via <"the Krib">.

I'd tend to ignore the extra potassium (K+) addition, but if you wanted to take it into account you could reduce the amount of potassium sulphate (K2SO4) you added.

cheers Darrel

 

[Zeus.]

I am using the ICF calculator to get the correct dosages. My questions are the following:

• Do I need to adjust the amount of Magnesium Nitrate since the calculator does not seem to have the Hexahydrate version (MgN2O6-6H2O)?

Which is the same as the hydrate on the IFC

its just noted in a different way

• I am planning to dose ~30 ml daily. So, 1 liter of the macro solution will last ~4 weeks. Should I add a stabilizer to the solution? If yes, what exactly will I need to add? I have seen a dozen different answers to this question...

You will probably be fine without with a fresh batch every four weeks, just disinfect bottle or at least have two use one whilst the other is empty air dry for four weeks.

Regarding the RO re-mineralizer. I was advised to use <this one> and to raise GH to 6° and KH to 3° (conductance of ~300µS). Could anyone give me some tips on how to produce a DYI re-mineralizer with a similar GH:KH ratio and a suitable Mg:Ca ratio?

Well I have done a more advanced remineralising section which allows easy cloning

Unfortunately, myself and @Hanuman have been busy and not had the time to polish it off and get it fit for release. If you post you tank size, amount of WC, whether you wish to use dry salts or make a solution and which salts you can get I will post the results of the amount of salts to add to make a clone. We was unable to find the exact Ca:Mg of Salty Shrimp+ from the data we have on the remineraliser - however a 3:1 ratio is what most shrimp keepers aim for
The remineraliser we can clone ATM are

 

[Zeus.]

Did a quick mix for your tank with a 50% WC

Three salts and just toss them in during adding the water at a yield of nearly 50ppm NO3
so 'if' your target NO3ppm is 30ppm heres a dry salt mix that will hit your NO3 and GH and KH

or for a stock solution to add for 125l WC

Then just dose your P K and trace elements on a separate regime during the week

Just post salts your can get M8

 

[MichaelJ]

Did a quick mix for your tank with a 50% WC
View attachment 178655
Three salts and just toss them in during adding the water at a yield of nearly 50ppm NO3
so 'if' your target NO3ppm is 30ppm heres a dry salt mix that will hit your NO3 and GH and KH
View attachment 178662
or for a stock solution to add for 125l WC

View attachment 178663
Then just dose your P K and trace elements on a separate regime during the week

Just post salts your can get M8

The almighty @Zeus. ... he always does my homework btw.

 

[arcturus]

Did a quick mix for your tank with a 50% WC

Many thanks for all the expert advice! Truly appreciated!

 

[arcturus]

A question, do I still need to add Potassium (K) with the suggested remin salts above? If I got it correctly, I will add the following NPK through the RO remin salts: ~30ppm NO3, ~42ppm K, zero PO4. So, I would just need to add the PO4 + micro/traces during the week. The NO3 and K would be dosed just 1x per week during the water change. Once again, many thanks!

 

[MichaelJ]

A question, do I still need to add Potassium (K) with the suggested remin salts above? If I got it correctly, I will add the following NPK through the RO remin salts: ~30ppm NO3, ~42ppm K, zero PO4. So, I would just need to add the PO4 + micro/traces during the week.

Yes, the potassium bicarbonate will add 41.83 ppm of K - all good. You still need to add some PO4 though, say ~5ppm. And of course traces... Make sure you get a trace blend that got it all in good quantities - this one is very good- unfortunately I dont think its available in the UK. @Zeus. can point you to a good product available in Europe.

Cheers,
Michael

 

[arcturus]

(...)
Unfortunately, myself and @Hanuman have been busy and not had the time to polish it off and get it fit for release. If you post you tank size, amount of WC, whether you wish to use dry salts or make a solution and which salts you can get I will post the results of the amount of salts to add to make a clone. We was unable to find the exact Ca:Mg of Salty Shrimp+ from the data we have on the remineraliser - however a 3:1 ratio is what most shrimp keepers aim for

Dear @Zeus: this is the composition of the two Salty Shrimp remineralizers <according to Carsten Logemann>, who is one of the Logemann brothers behind the Salty Shrimp company. Hope this info helps ading these two products to the ICF calculator Anyway, please try to check if these numbers make any sense... not sure if the information posted by Logemann is complete or correct...

<Shrimp Mineral GH/KH+> 13,89 % Calcium - Ca 5,39 % Magnesium - Mg 2,61 % Kalium - K 18,72 % Hydrogenkarbonat - HCO3 32,62 % Chlorid - Cl 17,27 % Sulfat - SO4 0,35985 % Spurenelemente - trace elements

<Shrimp Mineral GH+> 17,88 % Calcium - Ca 6,76 % Magnesium - Mg 2,11 % Kalium - K 0,69 % Hydrogenkarbonat - HCO3 41,50 % Chlorid - Cl 16,91 % Sulfat - SO4 0,35492 % Spurenelemente - trace elements

 

[arcturus]

Yes, the potassium bicarbonate will add 41.83 ppm of K - all good.

Thanks! This basically means I will be fertilizing with N+K macros just once per week together with the RO water remineralizer during the water change. So, the remaining days are only about adding PO4 + traces.

If ferts are added on a frequent basis then their concentration will be kept within a narrow range. But with 1x week fertilization, the concentration of N+K will gradually decrease throughout the week, which means that this approach might not provide a consistent availability of nutrients to the plants. Should I be concerned about this? The usual EI recommendation is to add macros 3x per week, correct?

Is it a better alternative to use a different water remineralization mix that minimizes N and K, so that these two macro elements can also be included during the week together with P + traces?

You still need to add some PO4 though, say ~5ppm. And of course traces... Make sure you get a trace blend that got it all in good quantities - this one is very good- unfortunately I dont think its available in the UK. @Zeus. can point you to a good product available in Europe.

At the moment I have plenty of a <liquid trace element solution> (with chelators EDTA, DTPA and HEEDTA). I will try to replace it with a trace salt blend going forward. Some individual trace elements are easy to buy, but not a trace blend - the market around here is mostly dominated by liquid fertilizer solutions.

 

[dw1305]

Hi all,

13,89 % Calcium - Ca
5,39 % Magnesium - Mg
2,61 % Kalium - K
18,72 % Hydrogenkarbonat - HCO3
32,62 % Chlorid - Cl
17,27 % Sulfat - SO4

Which sums to ~90%.

You should be able work out which salts they are using from this, but I'm struggling at the moment:

You're likely to use magnesium sulphate heptahydrate (MgSO4.7H2O), calcium chloride hydrate (CaCl2.nH2O) and potassium bicarbonate (KHCO3).

You need plus one more (bi)carbonate, because of the potassium to bicarbonate ratio. KHCO3 would provide ~ 3 : 7 K : HCO3 and we have ~3 : 19. Because it is only the carbonates of group one metals that are soluble some of the "missing" 10% is likely to be sodium bicarbonate (NaHCO3).

We also have some "spare" chloride, which may well be from sodium chloride (NaCl).

cheers Darrel

 

[Zeus.]

Dear @Zeus: this is the composition of the two Salty Shrimp remineralizers <according to Carsten Logemann>, who is one of the Logemann brothers behind the Salty Shrimp company. Hope this info helps ading these two products to the ICF calculator Anyway, please try to check if these numbers make any sense... not sure if the information posted by Logemann is complete or correct...

<Shrimp Mineral GH/KH+> 13,89 % Calcium - Ca 5,39 % Magnesium - Mg 2,61 % Kalium - K 18,72 % Hydrogenkarbonat - HCO3 32,62 % Chlorid - Cl 17,27 % Sulfat - SO4 0,35985 % Spurenelemente - trace elements

<Shrimp Mineral GH+> 17,88 % Calcium - Ca 6,76 % Magnesium - Mg 2,11 % Kalium - K 0,69 % Hydrogenkarbonat - HCO3 41,50 % Chlorid - Cl 16,91 % Sulfat - SO4 0,35492 % Spurenelemente - trace elements

Initial results are

However, I haven't got the dKH as it is the first time I have come across a data sheet giving the HCO3%. I have normally just got my hands on the dKH value and used that. The conversion from [CO3] to dKH and [HCO3] to dKH is different so will need to revisit that one before adding it to my copy, plus need to add a little to get the [SO4] as the spreadsheet it setup for S% not SO4%
Once we have all the ppms we should be able to work out what salts have been used (except for trace elements)
I even added Sodium Bicarbonate and Sodium Carbonate to my copy, which did enable me to make a better clone of some remineralisers - however I would advise using either of this salts myself, better to keep the Sodium [Na] as low as possible

 

[Zeus.]

Do like a puzzle

So sorted out the dKH just needed to revisit how its worked out and how we set up up on the IFC

The Bee Shrimp Mineral GH+ fits with the data sheet and what they claim approx 6GH

However the Shrimp mineral doesn't and I've checked the figures a few times quote 'It increases the total hardness (° dGH) and the carbonate hardness (KH) in proportion from ° dGH / KH: 1.0 / 0.5' which doesn't fit the datas results
Plus I am unsure if the quoted 6dGH is total hardness or just permanent hardness below

I had assumed it was total hardness when I first added the product months ago and hence I set the ratio and got 4dGH and 2dKH, but the data suggest not.
edit. UK site says its total hardness

Managed to make a reasonable clone of it but total mass was a little high using Sodium bicarb change the mass very little but did help close to the 3g per 20litres

Fold it harder to make a true clone of the Shrimp Mineral GH/KH+ and had to use sodium Bicarb to get close - but pretty close to the 2grams per 10litres
(I haven't added the image/ screen shot of the salts as it would yield a total Hardness of 8GH)

Cost wise Shrimp Mineral cost £12 per 100g and we have made a reasonable clone for £3 per kilo

On the present release IFC you can make bespoke remineralisers, and by playing with the Ca/Mg ppms (see last pic) just modify your actual WC figure and all the salts masses are sorted
I feel this is a very reasonable clone of Shrimp Mineral GH/KH+ and the mass per 10litres is very close

 

[Zeus.]

composition of the two Salty Shrimp remineralizers <according to Carsten Logemann>,

Found it really bugging me that the figures in the IFC calculator didn't work out with what the product claims of a total GH of approx 6GH and the composition in the link on their forum.
so went back to basics showing all conversions/maths
(Plus I wanted to confirm there was no errors on the IFC - if there was they would need prompt correction)

Plus the list of relevant conversions we have on the IFC

The maths was quite simple and a rough figure could be worked out mentally which would be in excess of a total GH above 6GH

I was going to post the results of the composition on the Salty Shrimp forum however the forum has closed

 

[Maf 2500]

Found it really bugging me that the figures in the IFC calculator didn't work out with what the product claims of a total GH of approx 6GH and the composition in the link on their forum.
so went back to basics showing all conversions/maths
(Plus I wanted to confirm there was no errors on the IFC - if there was they would need prompt correction)

Hi @Zeus. You have already included the temporary hardness in your calculations to convert ppm of calcium and magnesium to dGH. You are essentially counting the same molecules twice by including it again from the HCO3 ppm. The bottom section of the table should read:

Total hardness 6.37 dGH
Temporary hardness 1.72 dKH
Permanent hardness 4.65 dGH

This I think lines up more closely with what the manufacturer claims and explains why you didn't have the same issue for the product that didn't increase dKH/contain any HCO3.

 

[Zeus.]

Hi @Zeus. You have already included the temporary hardness in your calculations to convert ppm of calcium and magnesium to dGH. You are essentially counting the same molecules twice by including it again from the HCO3 ppm. The bottom section of the table should read:

Total hardness 6.37 dGH
Temporary hardness 1.72 dKH
Permanent hardness 4.65 dGH

This I think lines up more closely with what the manufacturer claims and explains why you didn't have the same issue for the product that didn't increase dKH/contain any HCO3.

My mistake for some reason I got it in my head that 'total hardness = permanent hardness + temporary hardness' which it isnt
The permanent hardness (GH) of water is determined by the concentration of multivalent cations in the water. So mainly Ca and Mg an other minor multivalent cations have a lesser effect on GH
Temporary hardness (KH) is caused by the presence of dissolved bicarbonate minerals, so HCO3 and CO3
Some salts give GH and KH like CaCO3 and MgCO3 but are not very soluble

Water is so complex it drives me nuts at times plus 'From a purely arithmetical point of view, it may not be possible to unravel everything exactly' 😬

Could do with @X3NiTH to enlighten us with his magic just to make sure we are barking up the right tree

 

[Maf 2500]

for some reason I got it in my head that 'total hardness = permanent hardness + temporary hardness' which it isnt

And to be fair I made a similar mistake in my post above by assuming the permanent and temporary hardness from the levels of dKH and dGH. Temporary hardness and carbonate hardness (KH) are not always the same thing although they are often used as synonyms for one another.

Water is so complex it drives me nuts at times plus 'From a purely arithmetical point of view, it may not be possible to unravel everything exactly' 😬

Yes, so many overlapping terms when talking about water hardness and not always used in the same way. Does my head in!