# Confused about mineral salts (EC/TDS) concerning shrimp tank



## Gilles (25 Apr 2022)

Question; i have bought an HM digital AP-2 tester to measure my conductivity of my R/O water unit. I want to (only) use R/O for my new tank and i want to get it up to 3.5 Kh.

If i look at the manual from Dennerle Remineral+ for example it states:





So adding 10g to 100l gives you:

1.3 Kh
2 dGH
140 conductivity
My shrimp breeder advised me to have a Kh between 3 and 4 for bee shrimp, so that would mean a conductivity between roughly 280 and 420. Isn't that too high?
I'll think i'll aim for a Kh of 3 for now which would mean roughly 23 grams for 100l

Thoughts/tips?


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## Gorillastomp (26 Apr 2022)

Idk if this can help you, uS/cm isnt the same as TDS. so if you are referencing to some TDS value from somewhere else, you need to convert it. Like 300uS/cm = 210 TDS


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## MichaelJ (26 Apr 2022)

Hi @Gilles,  I'm not familiar with Dennerle Remineral+,  but for Caridina cantonensis aka. Bee or Red Crystal Shrimps you need about 90-130 TDS (140-190 uS/cm - 180-260 uS/cm depending on conversion factor)  preferably at the lower range depending on the water the shrimps was bred and raised in (always ask your trusted breeder about tank parameters. Essentially TDS, GH, pH and temperature because thats what you ideally want to match within a reasonable range) - they need lower TDS  because they have a harder time regulating osmotic pressure compared to other hardier shrimps such as Cherry or Amano, but they still need a fair amount of Calcium to promote healthy exoskeleton development.  You should target ~20 ppm of Ca and ~6 ppm of Mg, this will put your water at 4-5 GH - that's it really. The remaining TDS (60-100 ppm) you can think of as a budget for fertilizers etc. for your plants (which is a lot of headroom). Don't worry about KH (xCO3) as long as its low. You can keep KH around 1 and use some botanicals to keep the pH in their preferred 6.2-6.8 range. And just make sure you feed them a good blend of algae, minerals and proteins and stay away of any fertilizers (traces) high on copper.

Cheers,
Michael


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## Wookii (26 Apr 2022)

Gilles said:


> My shrimp breeder advised me to have a Kh between 3 and 4 for bee shrimp, so that would mean a conductivity between roughly 280 and 420. Isn't that too high?
> I'll think i'll aim for a Kh of 3 for now which would mean roughly 23 grams for 100l



To add to @MichaelJ 's excellent post above, I've never seen a breeder keep Caridina in a KH above one, 0-1 is the usual range, perhaps with the exception of some hardier Tiger shrimp.


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## Nick potts (26 Apr 2022)

Agree with the above, a KH of 0-1 is fine for bee shrimp.



MichaelJ said:


> The remaining TDS (60-100 ppm) you can think of as a budget for fertilizers etc.


@MichaelJ sorry if I have read this wrong which is likely , are you saying the initial 4-5GH should only raise the TDS of the RO by 30ppm? I'm only asking as I aim for this GH but usually end up around the 90-95ppm range from just the MgSo4 and CaSo4.


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## ElleDee (26 Apr 2022)

1 ppm of a target nutrient is not equal to 1 TDS. Each ion has its own conductivity that varies and your TDS meter has a calibration solution that uses a specific salt as its basis for comparison. My meter uses NaCl, so if it says 150, the conductivity is equivalent to 150 ppm of table salt, but the actual concentration of what's in the tank is probably not going to add up to 150.

Plus you have to remember that both parts of a dissolved salt count towards TDS, so if you add epsom salt for magnesium you get the sulfate along with it.

I don't keep sensitive shrimp myself, but I've heard Salty Shrimp products are good for being efficient with TDS and taking the guesswork out. They are expensive for what they are though.


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## MichaelJ (26 Apr 2022)

Nick potts said:


> Agree with the above, a KH of 0-1 is fine for bee shrimp.
> 
> 
> @MichaelJ sorry if I have read this wrong which is likely , are you saying the initial 4-5GH should only raise the TDS of the RO by 30ppm? I'm only asking as I aim for this GH but usually end up around the 90-95ppm range from just the MgSo4 and CaSo4.



HI @Nick potts,  No, you didn't read it wrong.   But I should have been more clear when I said: _"The remaining TDS (60-100 ppm) you can think of as a budget for fertilizers etc."_

The _"etc."_  meant to include the largely unnessesary compounds we take on when we remineralize:

So if your using CaSO4 and MgSO4. when targeting 20 ppm Ca and 6 ppm of Mg.  Your should be getting an additional 16 ppm of S from CaSO4 and 8 ppm of S from MgSO4  or 50 ppm in total...   which leaves 40-80 ppm for NPK and traces.

In my own shrimp tank I use Ca Gluconate and CaSO4  and Mg Gluconate.  Nothing in the Ca Gluconate or Mg Gluconate, other than the Ca/Mg, will register at TDS.  The reason why I do not use 100% Ca Gluconate is because it tends to cloud up the water if I use too much and I also need a bit of S which I don't get from other sources.  With everything else I dose in terms of NPK and traces in my shrimp tank, my TDS sits around 90-100 ppm.   

Cheers,
Michael


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## Nick potts (26 Apr 2022)

Thanks @MichaelJ 

I may have to look at my dosing and see if what I am dosing correlates to TDS (I realise impurities etc can't be known) as mine is around 95 using Mgso4 and CaS04 and would always like to lower it/


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## MichaelJ (26 Apr 2022)

ElleDee said:


> 1 ppm of a target nutrient is not equal to 1 TDS. Each ion has its own conductivity that varies and your TDS meter has a calibration solution that uses a specific salt as its basis for comparison. My meter uses NaCl, so if it says 150, the conductivity is equivalent to 150 ppm of table salt, but the actual concentration of what's in the tank is probably not going to add up to 150.
> 
> Plus you have to remember that both parts of a dissolved salt count towards TDS, so if you add epsom salt for magnesium you get the sulfate along with it.
> 
> I don't keep sensitive shrimp myself, but I've heard Salty Shrimp products are good for being efficient with TDS and taking the guesswork out. They are expensive for what they are though.



Yes, thats the curse of TDS as a measure... it varies compound ppm vs. TDS    and the internal conversion factor in our probes can be 0.5, 0.64, 0.7  (they all internally measure uS/cm) depending on reference KCl NaCl, 442 etc...   Its a mess. I used to ramble about this a lot - eventually people got bored with me 

Cheers,
Michael


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## Nick potts (26 Apr 2022)

Mine  shows uS/cm as well, and it just doubles the reading for TDS.


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## MichaelJ (26 Apr 2022)

Nick potts said:


> Mine  shows uS/cm as well, and it just doubles the reading for TDS.


Same here... My hanna HI98301 DiST1 uses 0.5 as well...  as in uS/cm * 0.5 = TDS ppm. I have another brand that also uses 0.5.

Cheers,
Michael


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## MichaelJ (26 Apr 2022)

Nick potts said:


> Thanks @MichaelJ
> 
> I may have to look at my dosing and see if what I am dosing correlates to TDS (I realise impurities etc can't be known) as mine is around 95 using Mgso4 and CaS04 and would always like to lower it/


Yes, 95 seems way off... In my case the measurements with CaSO4 checks out pretty close.   If you have the individual salts try and measure in between adding so you can possibly spot which one may contain a lot of impurities. I do remember a bag of cheap MgSO4 I had didn't quite check out... hey, its Epsom salt it was supposed to be used in a bathtub as it turns out


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## ElleDee (26 Apr 2022)

MichaelJ said:


> Yes, thats the curse of TDS as a measure... it varies  and the internal conversion factor in our probes can be 0.5, 0.64, 0.7  (they all internally measure uS/cm) depending on reference KCl NaCl, 442 etc...   Its a mess. I used to ramble about this a lot - eventually people got bored with me


Yes, and then there's the question of if one's meter's even calibrated. Mine was supposed to arrive calibrated and I should be able to calibrate it myself ("with a small screw driver" but I haven't ever seen more specific instructions about how to do this) but have I ever even checked it? No. No, I have not. 😅

So I don't treat the specific reading as completely transferrable to other systems, I just use it as a general reference point. I know what my tap usually is and what my tanks are, so I can tell if the number is higher or lower than expected and that's good enough. I aim to keep it consistent, not to chase a specific number and I just don't keep anything that requires radically different water than what I have.


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## MichaelJ (26 Apr 2022)

ElleDee said:


> Yes, and then there's the question of if one's meter's even calibrated. Mine was supposed to arrive calibrated and I should be able to calibrate it myself ("with a small screw driver" but I haven't ever seen more specific instructions about how to do this) but have I ever even checked it? No. No, I have not. 😅
> 
> So I don't treat the specific reading as completely transferrable to other systems, I just use it as a general reference point. I know what my tap usually is and what my tanks are, so I can tell if the number is higher or lower than expected and that's good enough. I aim to keep it consistent, not to chase a specific number and I just don't keep anything that requires radically different water than what I have.



I agree.  As long as things measures out roughly as I would expect week over week based on my remineralization and fertilizer dosing I am fine, and that sets the baseline / reference point for me as well - any significant unanticipated deviation from that I take as a red flag. 

Cheers,
Michael


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## Gilles (28 Apr 2022)

So yesterday i added 4mg of my R/O minerals to 20l water and got a KH of 1.3 out of it (i use a Salifert KH test) and a μS value of around 169; which is in line with the table above.
Would that be a good start? (I have yet to measure the GH value of that water to be honest, see below)

p.s. from the HM website i see this:


> Most HM Digital TDS meters use the NaCl EC-to-TDS conversion factor, which is an average of 0.5.



As a side-note: I did mix 3 remineralisation salts into 1 container 
My salt is now an equal amount in grams of: Dennerle Remineral+ / JBL Aquadur (they both have the same usage instructions, so it would be OK to mix those) but i also added by mistake SaltyShrimp Bee Shrimp Mineral GH+ which does not impact the KH and only the GH. Therefore i will measure again my KH/GH and μS and report back.


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## dw1305 (28 Apr 2022)

Hi all,


Gilles said:


> So yesterday i added 4mg of my R/O minerals to 20l water and got a KH of 1.3 out of it (i use a Salifert KH test) and a μS value of around 169; which is in line with the table above.
> Would that be a good start? (I have yet to measure the GH value of that water to be honest, see below)


The <"_addition of a known weight of salts to RO water_"> method will be <"more accurate"> than the results from test kits for dGH and dKH (even from a good manufacturer <"like Salifert">).  The conductivity value (in microS) should be accurate, conductivity meters are pretty much <"_plug and play_">.

Also I would really recommend <"serial dilution">, it is much more accurate than trying to measure tiny weights.


Gilles said:


> My salt is now an equal amount in grams of: Dennerle Remineral+ / JBL Aquadur (they both have the same usage instructions, so it would be OK to mix those) but i also added by mistake SaltyShrimp Bee Shrimp Mineral GH+ which does not impact the KH and only the GH. Therefore i will measure again my KH/GH and μS and report back.


I'm not being funny, but if you bought "Epsom Salts" (MgSO4.7H2O),  "calcium chloride" (CaCl2.2H2O) (or "calcium sulphate" (CaSO4.2H2O)) and "potassium bicarbonate" (KHCO3) you could make up your <"remineralising solution"> <"for pennies">.

cheers Darrel


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