IFC Aquarium Fertilizer Calculator

[plantypus]

Hello Hanuman and thank you very much for your reply.

1. Do you have a compelling reason to use Full EI?

I'm only looking to use full EI until my plants grow to a satisfactory level and will then experiment to find a lean dosing regime that will keep the plants going without the need for a lot of water changes (will also have a look at Darrel's Duckweed Index suggestion as I've never heard of it before).

I should have perhaps mentioned that this is my first planted tank, it's just over a year old, started with around 20 different plants and used Tropica Specialised Nutrition to grow them to maturity doing 2 water changes and light trimming per week. Everything was going really well but then had to go abroad for 6 weeks. In order to keep the fish/shrimp/snails alive I asked some mates to pop round once a week and drop a holiday pellet. I was really expecting to come back to an algae fest and see all the plants dead and the livestock severely reduced but to my amazement all the fish survived (and multiplied) and despite many plants dying quite a few survived and actually did really well considering they only had some CO2 but no fertilisers. Algae was also present but very limited. I then decided to restart feeding the fish on a daily basis but add no fertilisers in order to do no water changes and observe the results. Now 7 months later I decided to do a huge clean up, add some more plants, start adding fertilisers and obviously restart the water changes. I don't really want to wait months for the plants to grow hence why I thought full EI was the way forward.

3. I would strongly recommend you do not integrate your calcium and magnesium targets in your macro fertilizer. Instead target them in your remineralisation scheme. At the very least calcium shoud definatly not be part of your macros. Mg could but it's best in my experience to do the same as with Ca. Dry dose them to your tank on WC day or pre-mix them in the water you will be adding to your tank on WC day.

So that I can get a better understanding, can I just ask why do you strongly advice to exclude calcium and magnesium from the macros?

 

[Hanuman]

I'm only looking to use full EI until my plants grow to a satisfactory level and will then experiment to find a lean dosing regime that will keep the plants going without the need for a lot of water changes (will also have a look at Darrel's Duckweed Index suggestion as I've never heard of it before).

Plants can grow more than satisfactorely with half (and even less) the dose of full EI. Remember these numbers are mere guidelines and I don't know many people, if anyone in fact, using full EI nowadays. These full EI dosing levels are reminicent from the early days of when Tom Barr popularized this regime. Those were many many years ago. We know better now.
Do note, I did not talk about "lean dosing" here. This is something else, entirely.

So that I can get a better understanding, can I just ask why do you strongly advice to exclude calcium and magnesium from the macros?

There are 3 main reasons:

1. Calcium compounds used for our purposes are usually not very soluble, Caclium Sulfate being extremely poorly soluable (see chart below), Calcium Chloride being the exception. Ok, so you said you use Calcium Chloride, so you may think this does not apply to you. Here comes reason 2;

2. You want to set the water hardness (dGH) in one time so that it is adequate from the begining and somewhat stable during the week and not progresively increased throughout the week, specially if you keep invertebrates. "I don't have invertebrates" I hear you say.... Here comes reason 3, and perhaps the most compelling one;

3. Because you would need to add major amounts of calcium in your macro solution in order to achieve the hardness targets each time you dose the solution in your tank, this would lead to precipitate forming in your solution due to the presence of other compounds. It is therefore highly advisable not to add calcium and magnesium in your macro solution. There is a reason why all these liquid fertilizers do not contain calcium. Most of thse products will contain some level of Magnesium as Magnesium can safely be added to the Macro solution and it is technically a macro nutrient. This said, all liquid fertilizer manufacturers assume the mineralization/remineralization of your water is for you to deal with, and rightlly so since water composition is virtually different everywhere. Also, often times the Mg content in these fertilizers is insufficient, specially for those using RO water, so you will still need to add more Mg to have a properly balanced water chemistry/hardness. Without going into details and for simplicity, Ca and Mg are the major compounds defining dGH.

If want to make a solution containing Calcium, then that's entirely possible but then it needs to be a sperate container from your macros. There is a note in the ReminCalculator which explains why if you select "Solution" instead of "Dry dosing". My opinion is that doing a solution to remineralize your water is best left to people with some experience. It can get tricky as you would need to have multiple containers and understand well what can and cannot be mixed together. IMO it is far easier to dry dose your Ca and Mg at each WC.

 

[John q]

So that I can get a better understanding, can I just ask why do you strongly advice to exclude calcium and magnesium from the macros?

When you mix Calcium chloride and Magnesium sulphate together you get a reaction, this reaction leads to the formation of Calcium Sulfate and Magnesium chloride, like Hanuman points out above Calcium Sulfate isn't very soluble and would end up falling out of solution in your dosing bottle.

 

[Hanuman]

When you mix Calcium chloride and Magnesium sulphate together you get a reaction, this reaction leads to the formation of Calcium Sulfate and Magnesium chloride, like Hanuman points out above Calcium Sulfate isn't very soluble and would end up falling out of solution in your dosing bottle.

That exactly. I should have started with that one which was probably more than enough. Got carried away with a novel.

 

[plantypus]

Hello Darrel,

thank you for your reply.

Are you adding CO2?

Yes, I currently do have a CO2 system going. It's actually working since day 1 and unlike the fertilisers I have not tried to stop using it but am not excluding the possibility.

I have a bit of an issue with Seachem <"Seachem method of potassium dosing">. Despite what they imply, there isn't a difference between the magnesium (Mg++) you add as a fertiliser, and the magnesium you add as a remineraliser, they are both the same ion.

I'm using Seachem Equilibrium because at the beginning of the aquarium I couldn't keep shrimps alive. This was sorted after starting dosing it with every water change.

If you aren't adding CO2? You might be interested in the <"Duckweed Index">.

I will certainly look into this and thank you very much for the suggestion.

 

[plantypus]

Plants can grow more than satisfactorely with half (and even less) the dose of full EI. Remember these numbers are mere guidelines and I don't know many people, if anyone in fact, using full EI nowadays. These full EI dosing levels are reminicent from the early days of when Tom Barr popularized this regime. Those were many many years ago. We know better now.
Do note, I did not talk about "lean dosing" here. This is something else, entirely.


There are 3 main reasons:

1. Calcium compounds used for our purposes are usually not very soluble, Caclium Sulfate being extremely poorly soluable (see chart below), Calcium Chloride being the exception. Ok, so you said you use Calcium Chloride, so you may think this does not apply to you. Here comes reason 2;

View attachment 217269

2. You want to set the water hardness (dGH) in one time so that it is adequate from the begining and somewhat stable during the week and not progresively increased throughout the week, specially if you keep invertebrates. "I don't have invertebrates" I hear you say.... Here comes reason 3, and perhaps the most compelling one;

3. Because you would need to add major amounts of calcium in your macro solution in order to achieve the hardness targets each time you dose the solution in your tank, this would lead to precipitate forming in your solution due to the presence of other compounds. It is therefore highly advisable not to add calcium and magnesium in your macro solution. There is a reason why all these liquid fertilizers do not contain calcium. Most of thse products will contain some level of Magnesium as Magnesium can safely be added to the Macro solution and it is technically a macro nutrient. This said, all liquid fertilizer manufacturers assume the mineralization/remineralization of your water is for you to deal with, and rightlly so since water composition is virtually different everywhere. Also, often times the Mg content in these fertilizers is insufficient, specially for those using RO water, so you will still need to add more Mg to have a properly balanced water chemistry/hardness. Without going into details and for simplicity, Ca and Mg are the major compounds defining dGH.

If want to make a solution containing Calcium, then that's entirely possible but then it needs to be a sperate container from your macros. There is a note in the ReminCalculator which explains why if you select "Solution" instead of "Dry dosing". My opinion is that doing a solution to remineralize your water is best left to people with some experience. It can get tricky as you would need to have multiple containers and understand well what can and cannot be mixed together. IMO it is far easier to dry dose your Ca and Mg at each WC.

View attachment 217268

Thank you for the extra detailed explanation Hanuman, I can understand a bit more about it now and will be dry dosing the magnesium sulphate and the calcium chloride after every WC going forward.

I will add the weekly dosing that was supposed to go to the macro solution into the remineralisation quantities (i.e add 4.4 grams of magnesium sulphate and the 3.97 grams of calcium chloride for a total dry dosing of 7.06 grams of magnesium sulphate and 4.41 grams of calcium chloride).

Many thanks!

 

[dw1305]

Hi all,

Yes, I currently do have a CO2 system going.

OK., it is likely that that your plants will have a higher demand for the mineral nutrients than if you weren't adding CO2. Light (PAR) drives photosynthesis and photosynthesis rates, in aquatic plants, are normally limited by lack of CO2 (<"Dissolved Inorganic Carbon">).

Because of the <"assembly line nature of plant growth"> when you add CO2 you need the <"fourteen essential mineral nutrients"> to be non-limiting, because if, even one, isn't available the plant can't utilise that "extra" CO2.

I'm using Seachem Equilibrium because at the beginning of the aquarium I couldn't keep shrimps alive. This was sorted after starting dosing it with every water change.

Cherry Shrimps <"don't like soft water">, so that may have been the reason. If you want a cheap option to add a bit of hardness and alkalinity (1 : 1 dGH : dKH) then <"Oyster Shell Chick Grit"> (sold for cage birds etc.) works fine <"Pets at Home Chicken Oyster Shell Supplement 1kg | Pets At Home"> If the link stops working that was £2 for 1 kg.

I have really hard tap water, <"(about 18 dGH : 18 dKH)"> so I can use that (and a <"sprinkle of "Epsom Salts">) as <"my re-mineraliser">. If I had soft tap water? I'd go down the Oyster Shell route.

There is nothing intrinsically wrong with "Seachem Equilibrium", the problem I have with it are:

• the cost,
• Seachem's advertising and
• the presence of a lot of potassium (K), that doesn't add either dGH or dKH.

I will add the weekly dosing that was supposed to go to the macro solution into the remineralisation quantities

Dry dosing makes sense with calcium and sulphate compounds, for the solubility reasons that @Hanuman & @John q mention. If you did want to go down the chick grit route? You could leave out the calcium chloride (CaCl2.nH2O).

I will certainly look into this and thank you very much for the suggestion.

The <"Duckweed Index"> was really designed for low tech plant keepers, but you can use it <"any situation">. I like lean dosing ("petrol fumes"), but others will use a <"lot more nutrients"> (<"triffid">*)

It uses a floating plant as your <"nutrient canary">, because floating plants have Diana Walstad's <"aerial advantage"> of <"access to atmospheric CO2"> (about <"424 ppm CO2"> today).

* I just use these ridiculous analogies so that I can re-find my posts

cheers Darrel

 

[plantypus]

Hello Darrel,

Hi all,
If you want a cheap option to add a bit of hardness and alkalinity (1 : 1 dGH : dKH) then <"Oyster Shell Chick Grit"> (sold for cage birds etc.) works fine <"Pets at Home Chicken Oyster Shell Supplement 1kg | Pets At Home"> If the link stops working that was £2 for 1 kg.

I have now spent £11 on 2kg of calcium chloride which will last me until October 2026 when it eventually expires but will then look into the Chicken Oyster Shell Supplement if it works out cheaper.

There is nothing intrinsically wrong with "Seachem Equilibrium", the problem I have with it are:

• the cost,
• Seachem's advertising and
• the presence of a lot of potassium (K), that doesn't add either dGH or dKH.

Why is there so much potassium in Seachem Equilibrium if it doesn't add either dGH or dKH? The ReminCalculator suggests that I dry dose 17.28 grams of Monopotassium Phosphate with every water change to reach the 100% of the potassium target. Do I really need to account for this in the remineralisation? I will be adding Monopotassium Phosphate in the macro solution but only a fraction of the dosage that is recommended for the remineralisation (0.23 grams weekly dosage in macros in comparison to 17.28 grams dry dosing after every WC for the remineralisation). The macro solution contains a weekly dosage of 1.36 grams of Potassium Sulphate that also contributes towards the potassium needs.

 

[dw1305]

Hi all,

but will then look into the Chicken Oyster Shell Supplement if it works out cheaper.

Calcium chloride (CaCl2.nH2O) just adds Ca++ ions (dGH) and that allows you to decouple dGH and dKH. Have a look at @Roland's <"soft water tank">. @Roland is also a Sheffield resident.

I have now spent £11 on 2kg of calcium chloride which will last me until October 2026 when it eventually expires

If you haven't used it all by then? It will last you a lot <"longer than that">, salts don't really have an expiry date. One thing to bear in mind is that CaCl2.nH2O is "deliquescent" and sucks up water like a sponge, so you would need to keep it in an air tight sealed container (or the freezer). I always assume that it will be the hexahydrate (CaCl2.6H2O) <"by the time you come to use it">, even if it was bought as the dihydrate (CaCl2.2H2O) if that makes sense? The difference in calculation is in the linked thread.

Why is there so much potassium in Seachem Equilibrium if it doesn't add either dGH or dKH?

The simple answer is that we don't know, and Seachem won't tell us, but I think this is the answer <"Seachem method of potassium dosing">.

....... Basically the potassium was present when it is mined - <"The formation of polyhalite: A 250-million-year-old story">, all Seachem do is put it in containers and slap an aspirationally priced label on it. They are all sulphate salts, but that is because that was what is present in the mineral deposit.

Basically it is a <"potassium based fertiliser"> (analysis below) that they've rebranded and sold as a remineraliser. It is a bit like selling a fruit cake, but only mentioning it is as a source of sultanas.

The percentage of potassium (K+) is 23 x 0.83 = 19% <"Which kind of potassium should I use?">)

I will be adding Monopotassium Phosphate in the macro solution but only a fraction of the dosage that is recommended for the remineralisation (0.23 grams weekly dosage in macros in comparison to 17.28 grams dry dosing after every WC for the remineralisation). The macro solution contains a weekly dosage of 1.36 grams of Potassium Sulphate that also contributes towards the potassium needs.

It doesn't matter where they have come from, every potassium (K+) ion is the same as every other one. Basically if you use <"Seachem Equilibrium"> you need to subtract its potassium addition from the total addition, and <"if you remineralise with calcium chloride and "Epsom Salts"> (MgSO4.7H20)? You don't.

<"Seachem Equilibrium"> analysis:

I'll be honest, personally I have a <"very slap-dash approach to adding nutrients">.

cheers Darrel

 

[MichaelJ]

Why is there so much potassium in Seachem Equilibrium if it doesn't add either dGH or dKH?

It adds dGH (no dKH) all right - Calcium and Magnesium in a good 3.3:1 ratio actually, but it also adds a stupendous amount of potassium - like 2.4:1 K:Ca - 8:1 K:Mg. so if you target say 4 dGH (common if you keep invertebrates) your going to get around 47 ppm of potassium! And that really makes the product less than desirable.

Cheers,
Michael

 

[John q]

The ReminCalculator suggests that I dry dose 17.28 grams of Monopotassium Phosphate with every water change to reach the 100% of the potassium target. Do I really need to account for this in the remineralisation?

No you don't need to add the Potassium Phosphate in the remineralisation calculations.

The Macro mix you worked out provides the 30ppm of weekly K you seek.

On a side note if you did go with the suggested 17.28g dry dosed Potassium Phosphate you'd have 92ppm of PO4 in the tank, that would certainly be one way of ensuring green spot algae never appeared 🙂

 

[MichaelJ]

92ppm of PO4 in the tank, that would certainly be one way of ensuring green spot algae never appeared 🙂

LOL … Not to mention that you probably would have to dose a lethal amount of iron to allow any bio-available iron for the plants. In any event, 92 ppm of PO4 equates 30 ppm of P which is routinely as much as 50-100 times what others would dose - it would be 300 times more than I dose. And no, I don’t have GSA… but I had at some point and I temporarily increased PO4 dosing to quell it - at least that’s what I thought.

The Macro mix you worked out provides the 30ppm of weekly K you seek.

Which is an insane amount of Potassium - regardless of tech level.

My densely planted low tech tanks are just fine with 1-2 ppm of K every two weeks.

I any event I strongly advice @plantypus to follow @Hanuman ’s and others advise above. As you get more experience etc you can explore more esoteric dosing venues. Stability is really the key.

Cheers,
Michael

 

[plantypus]

If you haven't used it all by then? It will last you a lot <"longer than that">, salts don't really have an expiry date.

There's an expiry date on the package and that's why I believed it would expire. I have purchased a 10L air tight container from ikea to keep all the salts in and will try to store it in a dry, cold, dark place.

One thing to bear in mind is that CaCl2.nH2O is "deliquescent" and sucks up water like a sponge, so you would need to keep it in an air tight sealed container (or the freezer). I always assume that it will be the hexahydrate (CaCl2.6H2O) <"by the time you come to use it">, even if it was bought as the dihydrate (CaCl2.2H2O) if that makes sense? The difference in calculation is in the linked thread.

Thanks for this, I had no idea!

In your post you say

Just add a third in weight for the hexahydrate.

and then you suggest

The calcium content of the hexahydrate (CaCl2.6H2O) is 18.3% (RMM = 219 (147 + 72)) and of the dihydrate (CaCl2.2H2O) 27% (RMM = 147), which means that:

If you needed to add 10g of CaCl2.2H20 to get to your calcium target, you need to add 15g of CaCl2.6H20.

This is 50% more and not a third as you mentioned before. Am I missing something?

It doesn't matter where they have come from, every potassium (K+) ion is the same as every other one. Basically if you use <"Seachem Equilibrium"> you need to subtract its potassium addition from the total addition, and <"if you remineralise with calcium chloride and "Epsom Salts"> (MgSO4.7H20)? You don't.

Many thanks for this, will only dose Magnesium Sulphate and Calcium Chloride for the remineralisation.

No you don't need to add the Potassium Phosphate in the remineralisation calculations.

Thanks John, this will save me a lot of potassium phosphate

I any event I strongly advice @plantypus to follow @Hanuman’s and others advise above. As you get more experience etc you can explore more esoteric dosing venues. Stability is really the key.

Will do Michael, it looks like I'll have to ditch the full EI dosing for something more reasonable, though will only be dosing this for a month tops until all the new plants/mosses pick up a bit.

 

[dw1305]

Hi all,

Am I missing something?

No, just poorly phrased (by me). This is correct:

The calcium content of the hexahydrate (CaCl2.6H2O) is 18.3% (RMM = 219 (147 + 72)) and of the dihydrate (CaCl2.2H2O) 27% (RMM = 147), which means that:
If you needed to add 10g of CaCl2.2H20 to get to your calcium target, you need to add 15g of CaCl2.6H20.

Will do Michael, it looks like I'll have to ditch the full EI dosing for something more reasonable,

I'm guessing that very few people with established tanks dose at full EI levels. Personally I'm always on the look out for slow growing plants that will limp along of <"petrol fumes">.

cheers Darrel

 

[plantypus]

Cheers for clarifying this Darrel I will take this into account when measuring up.

I have one more question with regards to Magnesium Sulphate and Calcium Chloride.

According to the ReminCalculator I should add 2.66 gr of Magnesium Sulphate and 0.44 gr of Calcium Chloride after every water change. This should increase dGH by 3.37 degrees.

According to the TargetCalculator when preparing a solution targeting EI Dosing Mid I should be adding 3.07 grams of Magnesium Sulphate and 2.52 grams of Calcium Chloride per week. This is a lot more than what is required for the remineralisation and will increase the dGH even further.

Is it reasonable and safe to dry dose the full weekly required amount by the TargetCalculator after the water change instead of the quantities worked out by the ReminCalculator?

 

[dw1305]

Hi all,

According to the ReminCalculator I should add 2.66 gr of Magnesium Sulphate and 0.44 gr of Calcium Chloride after every water change. This should increase dGH by 3.37 degrees.

According to the TargetCalculator when preparing a solution targeting EI Dosing Mid I should be adding 3.07 grams of Magnesium Sulphate and 2.52 grams of Calcium Chloride per week. This is a lot more than what is required for the remineralisation and will increase the dGH even further.

It doesn't matter where the calcium (Ca++) and magnesium (Mg++) ions come from, they aren't exclusive categories.

Is it reasonable and safe to dry dose the full weekly required amount by the TargetCalculator after the water change instead of the quantities worked out by the ReminCalculator?

The "Target Calculator" value is the one you want.

cheers Darrel

 

[Zeus.]

According to the ReminCalculator I should add 2.66 gr of Magnesium Sulphate and 0.44 gr of Calcium Chloride after every water change. This should increase dGH by 3.37 degrees.

According to the TargetCalculator when preparing a solution targeting EI Dosing Mid I should be adding 3.07 grams of Magnesium Sulphate and 2.52 grams of Calcium Chloride per week.

The target calculator and the remincalculator rarely (if ever )give the same results. Esp when comparing different targets

 

[hypnogogia]

According to the TargetCalculator when preparing a solution targeting EI Dosing Mid I should be adding 3.07 grams of Magnesium Sulphate and 2.52 grams of Calcium Chloride per week. This is a lot more than what is required for the remineralisation and will increase the dGH even further.

I’d leave that out of the EI mix and use the remineralisation dose, to keep dGH consistent and lower. It confused me at first as well.

 

[plantypus]

Hello and thank you for the replies guys.

I think I have mistakenly understood that the TargetCalculator suggests 3.07 grams of Magnesium Sulphate and 2.52 grams of Calcium Chloride per week. This looks to be x4 per week so the total would be 12.28 grams of Magnesium Sulphate and 10.08 grams of Calcium Chloride. Based on the GRAN TOTAL of amounts this should not raise the dGH above 5 so it shouldn't be a problem @hypnogogia . Another issue that might arise from dosing the recommended amounts from the remincalculator is that I will potentially be limiting the amount of calcium and magnesium required for the complete EI Dosing Mid.

@Zeus. I understand that the target calculator and the remincalculator give different results, I was just wondering if it is reasonable and safe to dose the full weekly recommended Calcium and Magnesium from the target calculator in a single dosage (i.e. 12.28 grams of Magnesium Sulphate and 10.08 grams of Calcium Chloride). I think @dw1305 has cleared this so I shall go ahead and dry dose these amounts after every water change.

Just for clarity I will take @Hanuman's advice and won't integrate the calcium and magnesium targets in the macro fertilizer.

 

[Zeus.]

I was just wondering if it is reasonable and safe to dose the full weekly recommended Calcium and Magnesium from the target calculator in a single dosage (i.e. 12.28 grams of Magnesium Sulphate and 10.08 grams of Calcium Chloride). I think @dw1305 has cleared this so I shall go ahead and dry dose these amounts after every water change.

Yes, Front loading the Ca and Mg is the best and easiest way to go IMO, two teaspoons of the former and two and a half teaspoons of the later for your 210 liter tank straight after WC and you good to go. It negates the solubility limits in the fert container and much reduces any possible interactions between any of the salts which may happen esp when in concentration in the fert container also.