What has a known alkalinity to check calibration

[BAMatter]

Looking to find a liquid that has an alkalinity in the 8-10dkh range so I can spot check my testers. Cant seem to find much other than the Hannah which has a dkh of 5 if im not mistaken and would like something closer to the levels my tanks run at. Thanks.

 

[BAMatter]

Could I take a gallon of RODI and add alk buffer according to this calculator and trust the results? No way of entering in 0 dkh for RODI…

 

[Randy Holmes-Farley]

Looking to find a liquid that has an alkalinity in the 8-10dkh range so I can spot check my testers. Cant seem to find much other than the Hannah which has a dkh of 5 if im not mistaken and would like something closer to the levels my tanks run at. Thanks.

A couple of thoughts...

1. If it is for a Hanna, I think needs to be a seawater solution to work properly.

2. I don't know of any consumer products that reliably have a specific total alkalinity near tank values.

3. A commercial standard can be a fine way to go, but then you are trusting the manufacturer.

A DIY can also work out.

 

[BAMatter]

A DIY can also work out.

Totally OK with DIY- is there a reliable suggestion you can throw my way? I currently have a Hanna checker, Hydros X10, and a Kamoer KH Carer, and I’d like to develop an offset to keep the honest honest and be able to spot errant readings. Or at least double check them before I dig into water issues.

 

[BAMatter]

A couple of thoughts...

1. If it is for a Hanna, I think needs to be a seawater solution to work properly.

2. I don't know of any consumer products that reliably have a specific total alkalinity near tank values.

3. A commercial standard can be a fine way to go, but then you are trusting the manufacturer.

A DIY can also work out.

Also- can I ask. If I use the Hannah 5dkh calibration set- is it a straight point for point up or down? Meaning, if say the 5dkh reads as 6dkh, can I translate that to reading 1dkh high regardless off what my seawater tests at, or is there some sort of logarithmic calculation that needs to be applied?

 

[Randy Holmes-Farley]

IMO, the best way to understand the accuracy of your three devices is to get an accurate measurement of your tank water, and test all three against it one after the other.

To do that, I'd buy a commercial acid standard, preferable 0.1 N HCl or H2SO4,a nd perform your own titration with a pH meter calibrated at pH 4 and 7:

A DIY Alkalinity Test: By Randy Holmes-Farley - REEFEDITION


THis one claims very high accuracy:

Sulfuric Acid Standard Solution, 0.100N, 100 mL MDB

Sulfuric Acid Standard Solution, 0.100N, 100 mL MDB

www.hach.com

 

[MnFish1]

Hanna sells alkalinity standards: https://www.bulkreefsupply.com/hi755-11-alkalinity-standards-for-hi755-hanna-checker-marine-water.html?ab_version=B&utm_term=&utm_campaign=EL+|+ACQ_Smart_Shopping+|+ROAS+|+All+Products&utm_source=adwords&utm_medium=ppc&hsa_acc=7373341438&hsa_cam=17740353356&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gclid=EAIaIQobChMIx7L3i8uZhAMVklBHAR3Y5AwgEAQYASABEgLmVfD_BwE

The standard is a somewhat low alkalinity - but if its the kit/method they recommend, why not use it?

 

[Randy Holmes-Farley]

Also- can I ask. If I use the Hannah 5dkh calibration set- is it a straight point for point up or down? Meaning, if say the 5dkh reads as 6dkh, can I translate that to reading 1dkh high regardless off what my seawater tests at, or is there some sort of logarithmic calculation that needs to be applied?

I do not think the Hanna is useful. It is just a color set that checks the electronics, not the actual alk measurement reagents or protocol.

 

[Randy Holmes-Farley]

Hanna sells alkalinity standards: https://www.bulkreefsupply.com/hi755-11-alkalinity-standards-for-hi755-hanna-checker-marine-water.html?ab_version=B&utm_term=&utm_campaign=EL+|+ACQ_Smart_Shopping+|+ROAS+|+All+Products&utm_source=adwords&utm_medium=ppc&hsa_acc=7373341438&hsa_cam=17740353356&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gclid=EAIaIQobChMIx7L3i8uZhAMVklBHAR3Y5AwgEAQYASABEgLmVfD_BwE

No, it's largely useless, IMO.. It is not anything but a color standard.

Hanna Checker Instructions for Marine Alkalinity Standards:

1. 1. Thoroughly wipe standard cuvette with HI731318 lint free cloth and only handle using top of cuvette. The cuvette wall must be dry and free of smudges.
2. 2. At the C. 1 prompt, place A, HI755-11 standard cuvette into the holder of the Checker and press operations button.
3. 3. At the C. 2 prompt, place B, HI755-11 standard cuvette into the holder of the Checker and press operations button.
4. Acceptable results must be between 90 and 110 ppm at 25°C

 

[spsick]

It’s pretty expensive imo but GHL sells a 7.5dkh reference solution.

KH Reference Solution 1000ml - ReefBum

Alkalinity reference solution for GHL KH monitors and test kits, 1000ml

www.reefbum.com

 

[MnFish1]

No, it's largely useless, IMO.. It is not anything but a color standard.

Hanna Checker Instructions for Marine Alkalinity Standards:

1. 1. Thoroughly wipe standard cuvette with HI731318 lint free cloth and only handle using top of cuvette. The cuvette wall must be dry and free of smudges.
2. 2. At the C. 1 prompt, place A, HI755-11 standard cuvette into the holder of the Checker and press operations button.
3. 3. At the C. 2 prompt, place B, HI755-11 standard cuvette into the holder of the Checker and press operations button.
4. Acceptable results must be between 90 and 110 ppm at 25°C

No what? It tells you if your hanna checker is reading correctly. I mean - the alkalinity test itself is just a color reading ---> a number, right?

 

[BAMatter]

It’s pretty expensive imo but GHL sells a 7.5dkh reference solution.

KH Reference Solution 1000ml - ReefBum

Alkalinity reference solution for GHL KH monitors and test kits, 1000ml

www.reefbum.com

Now we’re talking…

 

[MnFish1]

Totally OK with DIY- is there a reliable suggestion you can throw my way? I currently have a Hanna checker, Hydros X10, and a Kamoer KH Carer, and I’d like to develop an offset to keep the honest honest and be able to spot errant readings. Or at least double check them before I dig into water issues.

Just a question - How do you tell if, when you check alkalinity with your solution, and its different from what it should be where the problem is. I would suggest the way to test your hanna is to use another confirmatory test (i.e. a different brand) - using a standard would seem more useful if you could calibrate the hanna itself. I am not sure you can use the GHL standard to check the Hanna

 

[Randy Holmes-Farley]

No what? It tells you if your hanna checker is reading correctly. I mean - the alkalinity test itself is just a color reading ---> a number, right?

If the reagents are bad, your cuvettes are scratched, your timing is bad, etc, it tests none of that.

IMO, it should not be called an alkalinity standard.

It is more like a machine function check, not a standard.

A real standard would be, say, 8 dKH in seawater. Treat it just as you treat tank water in a test. Does it give 8 dKH? I expect they do not because folks would not like the results. lol

 

[Randy Holmes-Farley]

Now we’re talking…

Except that you do not know if it is accurate.

 

[BAMatter]

Just a question - How do you tell if, when you check alkalinity with your solution, and its different from what it should be where the problem is. I would suggest the way to test your hanna is to use another confirmatory test (i.e. a different brand) - using a standard would seem more useful if you could calibrate the hanna itself. I am not sure you can use the GHL standard to check the Hanna

I’m not sure. I have Hydros testing one of my tanks. KH Carer on another one. And a Hannah free floating around like the drifter that it is. Would love to find an offset for the Hannah to spot check the auto testers.

 

[BAMatter]

Except that you do not know if it is accurate.

You’re 100% correct. Or even if it will work on any of my testers. Lol.

 

[MnFish1]

If the reagents are bad, your cuvettes are scratched, your timing is bad, etc, it tests none of that.

IMO, it should not be called an alkalinity standard.

It is more like a machine function check, not a standard.

A real standard would be, say, 8 dKH in seawater. Treat it just as you treat tank water in a test. Does it give 8 dKH? I expect they do not because folks would not like the results. lol

Ok - totally agree. But - thinking about it, if the reagents are bad, your cuvettes are scratched or timing is off - the 8 DKH standard will have the same problems? I'm not arguing just trying to understand why not to use the test the manufacturer recommends?

 

[MnFish1]

I’m not sure. I have Hydros testing one of my tanks. KH Carer on another one. And a Hannah free floating around like the drifter that it is. Would love to find an offset for the Hannah to spot check the auto testers.

I would use another test kit that has about the same accuracy as the Hanna - if they disagree, there are 2 choices, 1 the hanna is wrong, 2. the other test is wrong. Good news is you have other tanks which 'known' alkalinities - that you can use to compare

 

[BAMatter]

I would use another test kit that has about the same accuracy as the Hanna - if they disagree, there are 2 choices, 1 the hanna is wrong, 2. the other test is wrong. Good news is you have other tanks which 'known' alkalinities - that you can use to compare

I’m coming to the conclusion that Salifert reads around .4dkh lower than both Hydros X10 and KH Carer, and that Hannah reads around .8dkh lower than X10 and KH Carer. I would love to have a certain dkh fluid or way to mix a certain dkh to test all 3.