CNDReef
Formally Toomanyfish
From my understanding is that the 0.1n is the concentrate like you get from alkatronic which you’ll have to dilute 1:4 with rodi
If you’re using the khd it would be straight 0.1n , no dilution necessary.
DIY Alkatronic reagent
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If you’re using the khd it would be straight 0.1n , no dilution necessary.
GoVols
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Someone correct me if I'm wrong, but h2so4 is the standard on all the popular automated testers. What acid would you recommend instead?
Based on the following post I was under the impression that hydrochloric acid evaporated. And because Randy never corrected him, I assumed it to be true.
sae74
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Thanks for the answer.
I am preparing myself 5 liters of reagent.
I have enough for 5 weeks.
I control the error in the tests "Hanna" - I did not notice any problems.
It is necessary for comparison to prepare H2SO4.
Randy Holmes-Farley
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At concentrations of 1 N or lower, both hydrochloric acid and sulfuric acid will slowly evaporate if open to the air, concentrating the acid a little bit. I would not assume hydrochloric acid is any more prone to changing concentration than is sulfuric acid when starting with these sorts of concentrations.
Stigigemla
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I had diluted hydrochloric acid in a 1,5 litre PET bottle for half a year. After that time it was unusable as kH reagent.
If You have diluted hydrochloric and sulfuric acid open You will notice a much stronger smell from the hydrochloric acid.
I see that as it evaporates more than sulfuric acid. But of coarse the smell i feel is not as exact as an analysis.
If You have diluted hydrochloric and sulfuric acid open You will notice a much stronger smell from the hydrochloric acid.
I see that as it evaporates more than sulfuric acid. But of coarse the smell i feel is not as exact as an analysis.
Randy Holmes-Farley
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I do not think you are understanding correctly. If you are talking about concentrated hydrochloric acid (>20% HCL), then yes, loss of acid is a concern.
But 1 N HCl or anything lower in concentration actually becomes a stronger acid, not weaker by loss of acid to the air. That happens because more water evaporates than HCL, concentrating it. The exact same thing happens with sulfuric: it gets concentrated as you let it evaporate because water evaporates and less or no acid.
Stigigemla
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I agree about the sulfuric acid getting more concentrated with water evaporating. I have experienced that with stains on clothes. It doesnt matter how diluted the acid is it will make holes in the clothes when the water from the acid dries.
But if You wash the clothes immediately it may go well.
My experience of HCl is different. I think I will make a test to see.
The experience of HCl and a pet bottle is from 2005 before I opened my shop.
I went out of Salifert kh reagent and with 2 x 120 miles to drive to buy new I decided to make my own.
I used a 1,5 litre PET bottle (ex carbonated mineral water) with RO water and calculated amount of HCl. I got the same results as with the ending Salifert test and was satisfied. I bought a new Salifert test and forgot the bottle in a shelf.
After half a year I saw the bottle again and tested it. The acid was now much weaker so I emptied the bottle.
But if You wash the clothes immediately it may go well.
My experience of HCl is different. I think I will make a test to see.
The experience of HCl and a pet bottle is from 2005 before I opened my shop.
I went out of Salifert kh reagent and with 2 x 120 miles to drive to buy new I decided to make my own.
I used a 1,5 litre PET bottle (ex carbonated mineral water) with RO water and calculated amount of HCl. I got the same results as with the ending Salifert test and was satisfied. I bought a new Salifert test and forgot the bottle in a shelf.
After half a year I saw the bottle again and tested it. The acid was now much weaker so I emptied the bottle.
Randy Holmes-Farley
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One can see from this paper that dilute hydrochloric acid gets more concentrated as it evaporates:
From Table 1, you can see that 1 M HCl (3.5 % HCl) has a vapor pressure of HCl of 0.00015 mm Hg HCl, and 16.8 mm Hg water, which is only 0.0009% HCl.
Thus, in dry air, what is evaporating is far lower in acid/water than in the 1 N solution,a nd the water must become more concentrated.
In humid air, there is already some water present, so that complicates it, but does not change the conclusion. Say it is very humid and the air is 80% saturated at 20 deg C.
Saturation of water at 20 deg C is 17.4 mm Hg, and 80% is 13.92 mm Hg.
Thus, 1 N HCl evaporating into 80% humid air will release 0.00015 mm Hg HCl and 16.8-13.9 mm Hg water, or 2.9 mm Hg.
Thus, 1 N HCl evaporating into 80% humid air at 20 deg C will be losing an effective concentration of 0.00015 mm Hg HCl and 2.9 mm Hg water, which has an effective concentration of 0.00015/2.9 * 100 = 0.005% HCl.
Thus, what is being evaporated off even in very humid air has a much lower acid concentration than the 1 N HCl,and the acid must be concentrating.
lexinverts
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Thanks!!
One 4L jug is on the way.
Are folks still using this Amazon Sulfuric Acid reagent for the alkatronic and running the waste line into their systems? Any evidence of long term negative effects?
I understand that the weak acid itself is not an issue, and only if there were some impurities in this LabChem Sulfuric Acid would there possibly be a long term impact on the tank.
Thanks for any experience that folks can share!
GoVols
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I’m just about to mix my first batch, and going to expel it back into the sump like the original.
Lol
Kinda hope it wipes out a big time Dino outbreak.
If I see any bad signs, then I’ll report back.
OP
OP
Used up the last of my mix. So it was time to try DIY with the LabChem .1n sulfuric acid from Amazon. Mixed 1:4 1250ml:5000ml rodi.
Recalibrated, ended up with a plugged nozzle and a worn out reagent tube. Replaced them, recalibrated everything. And letting it just run.
So far it's running 2 dkh higher than it should.
Alkatronic in orange
Trident in blue
Recalibrated, ended up with a plugged nozzle and a worn out reagent tube. Replaced them, recalibrated everything. And letting it just run.
So far it's running 2 dkh higher than it should.
Alkatronic in orange
Trident in blue
Randy Holmes-Farley
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So far it's running 2 dkh higher than it should.
Alkatronic in orange
Trident in blue
I don't have a dog in this fight, but how do you know which one is correct?
See and I was going to be more biased and say... "proof that the trident is off!"
In all honesty, the trident shows a lot bigger swing throughout a 24h period.
I know that it's using a rubber ruler, but when I see a significant drop or increase with the alkatronic, I bump it against hanna and it's always within 0.3 dkh.
There's no doubt that both units use an algorithm to determine the readings based on previous tests in order to minimize outliers. I also wonder which one is more correct?
OP
OP
Before using DIY both of them were running pretty close to each other, verified with hanna.
