Xepta AutoBalance reagent

elcapitan1993

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Hello I am purchasing a Xepta AutoBalance from Spain and am wondering does anyone know if the “reagent” used is just 0.1 N Hydrochloric acid or equivalent? It’s going to be difficult/expensive to get my hands on the Xepta brand reagent so I’m wondering what my options are for DIY reagent for this device, if anyone knows or can help it would be much appreciated.
 
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Dennis Cartier

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I was not aware that they had made their own KH tester. I would suspect that you can DIY the reagent. Every KH tester that I have run across uses a 0.1N acid standard.

I expect you can calculate the normalization they use as they give the info on their site for how many tests the bottles last for for a given sample size and KH value. I seem to remember someone posting the methodology for the calculation in the GHL alkalinity tester thread for DIY'ing the GHL reagent.
 
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elcapitan1993

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I was not aware that they had made their own KH tester. I would suspect that you can DIY the reagent. Every KH tester that I have run across uses a 0.1N acid standard.

I expect you can calculate the normalization they use as they give the info on their site for how many tests the bottles last for for a given sample size and KH value. I seem to remember someone posting the methodology for the calculation in the GHL alkalinity tester thread for DIY'ing the GHL reagent.
How do I go about doing that?
I haven’t been able to find a formula for calculating diy reagent

but that’s what I was thinking, almost If not all KH titration equipment lab or hobby grade use 0.1n acid
But what do you mean by normalization?
 

Dennis Cartier

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Ok, we got this!

The reagent here lists 330 test for a 50 ml sample at a KH of 8. The reagent is 1000 ml, so that means 3.03 ml per test.

The thread below shows that 0.02N reagent in a 8.0 KH, 50 ml sample, requires 7.15 ml of reagent.


So it looks like they are either using a 'custom' normalization (not off the shelf), or they have you dilute it a bit less than 0.04N. I don't see any place to access the instructions for their reagent. It may just be an off the shelf acid standard, like 0.1N, and diluted less than the other units use (4:1).

I read through their quick start guide. It does not mention diluting the reagent at all. So I think they sell it ready to use. Hmm, a bit of a waste shipping all that fluid. No matter, you can simply make your own using an off the shelf acid standard.

The odds are that I will probably mess up the calculation, so you may need one of the chemistry folk to double check it, but I would calculate it at:

7.15 ml / 3.03 ml = 2.3597359736 * 0.02N = 0.0471947195N <-- this is the normalization that you require of reagent (acid)

Ok, now let's see if we can calculate a dilution to get you there.

A dilution of 1:1.1188811189 gets you to a normalization of 0.0471947195N, which is what you need (if my calcs are right).

To do that multiply your 0.1N acid weight by 1.1188811189 to find out how much RODI you need to dilute it with.
 
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elcapitan1993

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Ok, we got this!

The reagent here lists 330 test for a 50 ml sample at a KH of 8. The reagent is 1000 ml, so that means 3.03 ml per test.

The thread below shows that 0.02N reagent in a 8.0 KH, 50 ml sample, requires 7.15 ml of reagent.


So it looks like they are either using a 'custom' normalization (not off the shelf), or they have you dilute it a bit less than 0.04N. I don't see any place to access the instructions for their reagent. It may just be an off the shelf acid standard, like 0.1N, and diluted less than the other units use (4:1).

I read through their quick start guide. It does not mention diluting the reagent at all. So I think they sell it ready to use. Hmm, a bit of a waste shipping all that fluid. No matter, you can simply make your own using an off the shelf acid standard.

The odds are that I will probably mess up the calculation, so you may need one of the chemistry folk to double check it, but I would calculate it at:

7.15 ml / 3.03 ml = 2.3597359736 * 0.02N = 0.0471947195N <-- this is the normalization that you require of reagent (acid)

Ok, now let's see if we can calculate a dilution to get you there.

A dilution of 1:1.1188811189 gets you to a normalization of 0.0471947195N, which is what you need (if my calcs are right).

To do that multiply your 0.1N acid weight by 1.1188811189 to find out how much RODI you need to dilute it with.
Thank you so much! I appreciate it
I’m seriously terrible at chemistry calculations

I had to dilute 1.0 n HCL to 0.1 n and that took me hours to do lol

they do sell “concentrated” reagent in a 5l container witch says it makes 20 liters, I don’t know if that helps you figure anything out though

right now I have 10 liters of 0.1 n HCL that I was using on the GHL kh director, it would have been nice to be able to just use it as is for regent for the xepta but it looks like that won’t be the case.

im thinking I should order 5 l of xepta reagent so it can help me pinpoint

let’s say if I test the ph of the xepta reagent and then test my DIY reagent l, if the ph of both are the same would that mean that the “concentration” is also the same?
 

Dennis Cartier

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Ordering the 5L of reagent to give you something to use while you get your DIY version worked out sounds like a good plan.

I would use the 0.1N HCL for testing the dilution required to match the KH measurement of the OEM reagent.

So they are diluting, based on the 5L to 20L, that would be 3:1. I would try dosing a 3:1 dilution of your 0.1N that you have on hand, just in case they are using the same as everyone else is.

Measuring the pH will not help you to determine the normalization unfortunately.
 
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elcapitan1993

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Ordering the 5L of reagent to give you something to use while you get your DIY version worked out sounds like a good plan.

I would use the 0.1N HCL for testing the dilution required to match the KH measurement of the OEM reagent.

So they are diluting, based on the 5L to 20L, that would be 3:1. I would try dosing a 3:1 dilution of your 0.1N that you have on hand, just in case they are using the same as everyone else is.

Measuring the pH will not help you to determine the normalization unfortunately.
So then I need to dilute the 0.1 with 3 liters or RO/DI water for every 1 liter of 0.1 HCL?

yeah if I have their reagent then I can test with that and try and match the readings with my DIY reagent and then I will know what concentration I need for the future
It sucks because it’s going to cost me 150$ just to get the 5l reagent, at least I can order concentrate and that will make 20 liters witch will help, do you know if there are any other kh testers in the USA that isn’t the kh director or alkatronic
The alkatronic is chronically out of stock or I would get that
 
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elcapitan1993

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Ordering the 5L of reagent to give you something to use while you get your DIY version worked out sounds like a good plan.

I would use the 0.1N HCL for testing the dilution required to match the KH measurement of the OEM reagent.

So they are diluting, based on the 5L to 20L, that would be 3:1. I would try dosing a 3:1 dilution of your 0.1N that you have on hand, just in case they are using the same as everyone else is.

Measuring the pH will not help you to determine the normalization unfortunately.
On the concentrated reagent to make 1000 ml it says to do 250 ml of concentrated reagent and 750 ml of RO/DI water, I have no idea what ratio that is, I finally received the auto balance and need to start testing DIY versions
 

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You made a DIY version of the reagent? Just to confirm, you used a 0.1N standard and diluted it 3:1? Finally, was it 1 dKH too high or low?

Also how much did you make? The mixed amount will determine what a 1-3ml measurement error will affect.
 
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elcapitan1993

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You made a DIY version of the reagent? Just to confirm, you used a 0.1N standard and diluted it 3:1? Finally, was it 1 dKH too high or low?

Also how much did you make? The mixed amount will determine what a 1-3ml measurement error will affect.
Yes I did, it correct it was 0.1N HCL , I did 250ml of HCL and 750ml RO/DI water, it was 1DKH to low, I’m going to make another batch and do it slower this time and make sure I didn’t accidentally skip a step, but I don’t think I made a mistake, since it was 1DKH LOW that means I should add more water to it right?
 

Dennis Cartier

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Ok, let's see if this straight forward just based on the error. Can you multiply your water amount by 1.1 please?

So if you were using 750ml, please use 825ml.

Let's see where that gets you.
 

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