Remineralizing question

[Hanuman]

I am using RO. I have been remineralizing my tank for the past year (Ca:Mg / 3:1 / 20ppm:6.67ppm) with CaSO4 and MgSO4 not really considering the amount of sulfate being added, but considering I have had most my Panda Garra die one after the other for the past weeks I am looking for answers. I don't think this is the reason but I am taking the opportunity to improve things. So the question is: what would be preferable:

1. Magnesium sulphate + Calcium chloride

total ~92ppm of Cl+SO4
or
2. Magnesium chloride + Calcium sulfate?

total ~83ppm of Cl+SO4
or
3. Magnesium sulphate + Calcium sulfate

total ~ of 121ppm of SO4

Instinct says 2. Magnesium chloride + Calcium sulfate due to lower overall ppm value but I am no biologist hence my question.

I am also considering adding some Magnesium Carbonate (or even Calcium Carbonate which I have readily available although extremely insoluble and only useful for 0.5 degree) to slightly raise my KH by 0.5 or even 1 degree. Yesterday I measured the water and I had 1dKH. In fact I am thinking if this low Kh is not the reason why my Panda Garra have left to the other world. Now that I remember I changed my filter cartridges and RO membrane in January and wonder if that is not the reason for all this shenanigans.

In any case thanks for the input.

 

[Hanuman]

As a side note, I have been looking for Magnesium chloride and only seem to be able to find what they call "technical grade or "industrial grade" MgCl2. This is the certificate of analysis of a supplier:

Would this be acceptable for aquarium use?

 

[medlight]

Remineralizo con Caso4+CaCl+ MgSo4, la relación entre SO4 y Cl 3:1

 

[Wookii]

I use MgSO4 and CaCl2 - the latter dissolves very easily, and both salts are widely available (over here in the UK at least).

You could also consider Magnesium Nitrate and/or Calcium Nitrate if you can source it, and wanted to reduce the amounts of Cl and SO4.

 

[Hanuman]

You could also consider Magnesium Nitrate and/or Calcium Nitrate

I rather not touch the nitrate for now as that is being provided by my AIO fert which I still have plenty but something to consider later on.

I have been trying to source Magnesium chloride but for some reason I can only source industrial grade and I don't feel that comfortable with that. Best bet would be Calcium chloride as that one I can find food grade.

 

[dw1305]

Hi all,

Would this be acceptable for aquarium use?

It would depend on which salt the other ~50% was. It may just be the <"water of crystallization"> because I'm assuming that both CaCl2 and MgCl2 are the hexahydrate form, MgCl2.6H2O etc.

Magnesium chloride + Calcium sulfate due to lower overall ppm value but I am no biologist hence my question.

I am also considering adding some Magnesium Carbonate (or even Calcium Carbonate

I use MgSO4 and CaCl2

I would just use "Epsom Salts" (magnesium sulphate heptahydrate (MgSO4.7H2O)) and ~10% Mg and <"a smidgen">* of calcium carbonate (CaCO3) to add Ca and dKH. If you didn't want to add any dKH then CaCl2.6H2O is your go to chemical.

If you did use Mg(NO3)2.6H2O then adding 10 ppm (mg/l) Mg would also add 51 ppm NO3 and you would have to take into account the water of crystallization, so the RMM would be 256 and 9.5% Mg and 48% NO3.

*Specially for @Hufsa

cheers Darrel

 

[Hanuman]

It would depend on which salt the other ~50% was. It may just be the <"water of crystallization"> because I'm assuming that both CaCl2 and MgCl2 are the hexahydrate form, MgCl2.6H2O etc.

Yes they are the hexahydrate forms. That's what I thought as well, mostly water. But since usually industrial grades are less refined there could be some lead or other nasty stuff in there to levels which are not disclosed. I was able to find CaCl2 food grade though so I guess I'll just forget about MgCl2.

I would just use "Epsom Salts" (magnesium sulphate heptahydrate (MgSO4.7H2O) and ~10% Mg and smidgen of calcium carbonate (CaCO3) to add Ca and dKH.

That's what I did earlier this morning before leaving to work to slightly increase dKH. But I did a goal seek calculation and it shows me that the max dKH I can have before I reach the in-tank solubility limit of CaCO3, is 0.6 dKH (max 0.8 dKH if I increased solubility setting to 100% - which is not a good idea). If I wanted to increase dKH more than that I would need to use something else and that something else can only be Magnesium carbonate as I don't want to start adding other ions like Potassium, Nitrates or whatnot. That's why I considered Magnesium Carbonate as that is way more soluble.

 

[dw1305]

Hi all,

But I did a goal seek calculation and it shows me that the max dKH I can have before I reach the in-tank solubility limit of CaCO3, is 0.6 dKH

Yes, technically CaCO3 is insoluble in water, but soluble in weak acids. You can actually use this to your advantage, it gives you a negative feedback loop where the Ca++ and 2HCO3- ions only go into solution when the pH dips. Plants don't have a huge calcium requirement, so it should fulfill that.

If you have <"hard tap water you can use that"> or you can just add a bit of limestone to the tank. I'm going to assume caged bird keeping is popular in Thailand, so shell grit should be available?

cheers Darrel

 

[Wookii]

I did a goal seek calculation and it shows me that the max dKH I can have before I reach the in-tank solubility limit of CaCO3, is 0.6 dKH

You are injecting CO2 aren't you? In which case you'll dissolve much more CaCO3 and get a much higher dKH. In my last tank I had a load of Seiryu stone which had lots of CaCO3 in it, and despite doing water changes with pure un-mineralised RO, the tank maintained a pretty consistent KH of around 6, and a GH of 11-12, just from the dissolved CaCO3 from the rock and MgSO4 in the EI ferts.

 

[Hanuman]

Yes, technically CaCO3 is insoluble in water, but soluble in weak acids

Indeed. I omitted that very essential part. Thank you.

If you have <"hard tap water you can use that"> or you can just add a bit of limestone to the tank. I'm going to assume caged bird keeping is popular in Thailand, so shell grit should be available?

I use RO. Yes caged bird is popular in Asia in general. I think cuttlebone is also easily found considering all the squid they eat around here.

You are injecting CO2 aren't you? In which case you'll dissolve much more CaCO3 and get a much higher dKH

Yes. That meets what Darrel said above. The solubility of all those compound with have in the calculator are based on neutral water at 20 degrees.

In my last tank I had a load of Seiryu stone which had lots of CaCO3 in it, and despite doing water changes with pure un-mineralised RO, the tank maintained a pretty consistent KH of around 6, and a GH of 11-12, just from the dissolved CaCO3 from the rock and MgSO4 in the EI ferts.

Yes. I had considered having some stone initially. It could be same as adding some shell or cuttlebone. I might start with a small piece and increase progressively until I read desired dKH but that might take several weeks to have consistent readings.

 

[Wookii]

Yes. I had considered having some stone initially. It could be same as adding some shell or cuttlebone. I might start with a small piece and increase progressively until I read desired dKH but that might take several weeks to have consistent readings.

Yeah, I wasn't suggesting you use stone to add CaCO3, the cuttlebone or oyster shell grit will be a better way to add it 'naturally' - more that you'll end up at a higher KH level than you expected from your calculations due to the carbonic acid.

I've always wanted to try and use the cuttlebone or oyster grit approach, but I think its going to be difficult to regulate in a CO2 injected tank, whereas adding KHCO3 or K2CO3 is easier to accurately control (though I appreciate that you don't want to add the extra potassium).

 

[Hanuman]

I've always wanted to try and use the cuttlebone or oyster grit approach, but I think its going to be difficult to regulate in a CO2 injected tank, whereas adding KHCO3 or K2CO3 is easier to accurately control (though I appreciate that you don't want to add the extra potassium).

Yes much easier considering you know exactly what you are adding. I might just stick to CaCO3. Reality is I don't need to increase dKH that much maybe 1 point up at most. I need to measure dKH at the end of the week before WC to see what the new reading is.

 

[Wookii]

Yes much easier considering you know exactly what you are adding. I might just stick to CaCO3. Reality is I don't need to increase dKH that much maybe 1 point up at most. I need to measure dKH at the end of the week before WC to see what the new reading is.

If you are happy to dry dose, that's probably the best way forward for you. It doesn't work for me, as I automate everything with auto-dosers, and the CaCO3 is too insoluble to be able to use in a concentrated liquid.

 

[X3NiTH]

Here’s what I do for remineralisation with Calcium and Magnesium Carbonate, I previously posted here in another thread, it’s an attempt at simulating Karst waters.

Add to 900ml Refrigerated Cold Carbonated RO/DI (one full level round in new type soda stream machine is enough)-

2g Calcium Carbonate
1g Magnesium Bicarbonate
0.25g Ascorbic Acid

In order to keep as much CO₂ from off gassing the above mixture is added to a food spice diffusion bag and placed fully and quickly into the neck of the briefly open bottle, above the cold pressurised water making sure to close the top tightly before shaking to mix (adding the powder without the bag can turn the water into a volcano, not quite bicarbonate into vinegar but it gets close). This mix goes back into the fridge for 24hrs just to give it time to go somewhat into solution, it's more of a suspension that can sediment but over 24hrs there is a massive reduction in sedimentation happening and the liquid takes on a cloudy lemonade look telling me some bicarbonate has formed, when the bottle is reagitated and the sedimentation goes back into suspension the resultant liquid looks like skimmed milk (importantly the mix has fully exited the spice bag by this time).

A day before performing the water change I will add to the 24.1L (or thereabouts water volume it may be more, I just need enough space in there to take the 900ml back and not spill over the lip when the Jerry can is sitting upright and level)-

1g Potassium Bicarbonate
0.75g Magnesium Nitrate
0.5g Magnesium Sulphate
0.2g Potassium Phosphate
Pinch of Magnesium Chloride

I don't measure the Magnesium Chloride out because it really is just a teeny tiny pinch just enough so Chloride is non-zero hence its magnesium content I don't add to the final numbers I'll give below.

Once these salts are in the water in the Jerry can I then take the cold bottle of bicarbonate/carbonate solution from the fridge and add it all in (opening the bottle slowly and no vigorous agitation beforehand as to not off gas too much CO₂), fish out the empty spice bag floating at the top and pour half the liquid into the Jerry can, the remaing liquid in the bottle is given a swirl around to pick up any sedimentation and poured directly into the Jerry can, I then seal the top and leave it overnight to go clear.

24hr dwell time for everything in the water is not any special number it's just the minimum time I have so far left it to sit before use and since I do two jerry cans at a time. The other end of the wait spectrum is a Jerry can sitting 2 weeks before use with CO₂ still being retained at 30-35ppm.

The resultant values in mg/L are (resultant water TDS <150) -

Ca / 32
Mg / 14.42 (not counting MgCl addition)
K / 17.9
NO₃ / 15
PO₄ / 5.58
S / 2.6
Cl / Non zero

GH / 7.8 (MgCl addition probably pushes this to nearer 8)
KH / 7.8
pH / 7.8 (@ atmospheric CO₂ from stored sample which correlates with in tank behaviour)

In tank CO₂ injection phase behaviour -
pH / 6.2 (estimated 30ppm CO₂ via Lime Green colour change to Drop Checker 4dKH sample)

The recipe is easily adapted, I have tried dosing the carbonates of Calcium and Magnesium dry into a CO2 injected tank and it took a week or so of injection phases for the Calcium to fully dissolve and not look like a fine dusting of snow on the substrate.

I did end up here from using Cuttlefish Bone for remineralisation but wanted something quicker so I turned the Cuttlefish bone into dust and dosed that and it worked a lot faster (finer the powder the greater the surface area to volume), hands stank of fish for a bit afterwards and opted to skip that step and source the pure carbonates instead.

 

[Happi]

@Hanuman

I believe the So4 numbers are incorrect in the first post.

Target:
Ca 20
Mg 6.67

1. Magnesium sulphate + Calcium chloride
Cl 35.38
So4 26.4

2. Magnesium chloride + Calcium sulfate
Cl 19.46
So4 48

3. Magnesium sulphate + Calcium sulfate
So4 74.4

 

[Happi]

you can also add some Ca and Mg Gluconate to your mix, this is good food source for bacteria as well, if your aquarium condition are right this will also help to reduce the NO3 if you were to use Ca and Mg Gluconate.

 

[Hanuman]

Here’s what I do for remineralisation with Calcium and Magnesium Carbonate, I previously posted here in another thread, it’s an attempt at simulating Karst waters.

Add to 900ml Refrigerated Cold Carbonated RO/DI (one full level round in new type soda stream machine is enough)-

2g Calcium Carbonate
1g Magnesium Bicarbonate
0.25g Ascorbic Acid

In order to keep as much CO₂ from off gassing the above mixture is added to a food spice diffusion bag and placed fully and quickly into the neck of the briefly open bottle, above the cold pressurised water making sure to close the top tightly before shaking to mix (adding the powder without the bag can turn the water into a volcano, not quite bicarbonate into vinegar but it gets close). This mix goes back into the fridge for 24hrs just to give it time to go somewhat into solution, it's more of a suspension that can sediment but over 24hrs there is a massive reduction in sedimentation happening and the liquid takes on a cloudy lemonade look telling me some bicarbonate has formed, when the bottle is reagitated and the sedimentation goes back into suspension the resultant liquid looks like skimmed milk (importantly the mix has fully exited the spice bag by this time).

A day before performing the water change I will add to the 24.1L (or thereabouts water volume it may be more, I just need enough space in there to take the 900ml back and not spill over the lip when the Jerry can is sitting upright and level)-

1g Potassium Bicarbonate
0.75g Magnesium Nitrate
0.5g Magnesium Sulphate
0.2g Potassium Phosphate
Pinch of Magnesium Chloride

I don't measure the Magnesium Chloride out because it really is just a teeny tiny pinch just enough so Chloride is non-zero hence its magnesium content I don't add to the final numbers I'll give below.

Once these salts are in the water in the Jerry can I then take the cold bottle of bicarbonate/carbonate solution from the fridge and add it all in (opening the bottle slowly and no vigorous agitation beforehand as to not off gas too much CO₂), fish out the empty spice bag floating at the top and pour half the liquid into the Jerry can, the remaing liquid in the bottle is given a swirl around to pick up any sedimentation and poured directly into the Jerry can, I then seal the top and leave it overnight to go clear.

24hr dwell time for everything in the water is not any special number it's just the minimum time I have so far left it to sit before use and since I do two jerry cans at a time. The other end of the wait spectrum is a Jerry can sitting 2 weeks before use with CO₂ still being retained at 30-35ppm.

The resultant values in mg/L are (resultant water TDS <150) -

Ca / 32
Mg / 14.42 (not counting MgCl addition)
K / 17.9
NO₃ / 15
PO₄ / 5.58
S / 2.6
Cl / Non zero

GH / 7.8 (MgCl addition probably pushes this to nearer 8)
KH / 7.8
pH / 7.8 (@ atmospheric CO₂ from stored sample which correlates with in tank behaviour)

In tank CO₂ injection phase behaviour -
pH / 6.2 (estimated 30ppm CO₂ via Lime Green colour change to Drop Checker 4dKH sample)

The recipe is easily adapted, I have tried dosing the carbonates of Calcium and Magnesium dry into a CO2 injected tank and it took a week or so of injection phases for the Calcium to fully dissolve and not look like a fine dusting of snow on the substrate.

I did end up here from using Cuttlefish Bone for remineralisation but wanted something quicker so I turned the Cuttlefish bone into dust and dosed that and it worked a lot faster (finer the powder the greater the surface area to volume), hands stank of fish for a bit afterwards and opted to skip that step and source the pure carbonates instead.

This requires some serious skills far above and beyond my pay grade 😅.

 

[Hanuman]

I believe the So4 numbers are incorrect in the first post.

Target:
Ca 20
Mg 6.67

1. Magnesium sulphate + Calcium chloride
Cl 35.38
So4 26.4

2. Magnesium chloride + Calcium sulfate
Cl 19.46
So4 48

3. Magnesium sulphate + Calcium sulfate
So4 74.4

Nope. Figures are correct. On the other hand you used values relating to the anhydrous states of those salts (CaSO4 and MgSO4) which gives you the values you found. In general it is far more common to find the hydrate versions, for instance CaSO4·2H2O (Calcium sulfate dihydrate) and MgSO4‧7H2O (Magnesium sulfate heptahydrate).

 

[Happi]

Nope. Figures are correct. On the other hand you used values relating to the anhydrous states of those salts (CaSO4 and MgSO4) which gives you the values you found. In general it is far more common to find the hydrate versions, for instance CaSO4·2H2O (Calcium sulfate dihydrate) and MgSO4‧7H2O (Magnesium sulfate heptahydrate).

Just to be clear which one did you use in your first post?

 

[Hanuman]

The hydrate forms. CaSO4·2H2O and MgSO4‧7H2O which is what I use.