What has a known alkalinity to check calibration

[Randy Holmes-Farley]

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?

A real 8 dKH standard in seawater that gives a result of 8 dKH is a very good indication that if you test your tank water under the same conditions and get 9 dKh, it is likely (not guaranteed) to be accurate. A couple of standards spanning your tank walk would be even better.

But just testing the machine electronics and photonics leaves out the most common sources of error with these tests: bad reagents, scratched cuvettes, and bad human actions (timing, etc.).

To be honest, I've never heard anyone report their Hanna filed a colored water check.

 

[Randy Holmes-Farley]

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.

Which is what I provided. A way to make a standard that you know is accurate.

You could alternatively buy a base standard (0.01 N NaOH = 28 dKH) that will work for a titration alk test, but likely not the Hanna.

 

[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

What if theyre all wrong? Which I’m assuming they are. Guess this is what I’m looking for is a tried and trued solution that is “#”dkh, so I can see how off they all are.

 

[BAMatter]

Which is what I provided. A way to make a standard that you know is accurate.

You could alternatively buy a base standard (0.01 N NaOH = 28 dKH) that will work for a titration alk test, but likely not the Hanna.

Thanks Randy !

 

[MnFish1]

What if theyre all wrong? Which I’m assuming they are. Guess this is what I’m looking for is a tried and trued solution that is “#”dkh, so I can see how off they all are.

This is an issue with every 'test' (not just saltwater, not just aquaria - but every test). First all of the 'tests' you're using have a different accuracy and precision. So that has to be accounted for. And let's say you measured your variety of methods - and one time you got 8.3 DKH and an hour later you got 7.9 DKH, both tests may be 'right' depending on the test used. Also - a lot of alkalinity can vary through different times of the day - so it's best to test at the same time.

 

[jlitz]

Which is what I provided. A way to make a standard that you know is accurate.

You could alternatively buy a base standard (0.01 N NaOH = 28 dKH) that will work for a titration alk test, but likely not the Hanna.

What alkalinity tester do you recommend? I’ve had a hard time reading the redsea alk titration (not the best eyes) so I switched to the hannah checker but I don’t know whether I fully trust it yet.

 

[Randy Holmes-Farley]

What alkalinity tester do you recommend? I’ve had a hard time reading the redsea alk titration (not the best eyes) so I switched to the hannah checker but I don’t know whether I fully trust it yet.

I don't have a particular brand I recommend and many are suitable. Many folks seem to like the Salifert kit.

Personally, I prefer a DIY:

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

Alkalinity is one of the most important measurements that a reef aquarist can make. It can become rapidly depleted in many aquaria, requiring frequent measurement in order to maintain stable levels.

www.reefedition.com

 

[BAMatter]

@Randy Holmes-Farley in another potential universe where Randy # 2 thinks that the Hannah alk calibration kit at 5dkh is reliable and the best way to calibrate and find an accurate alk reading, in the circumstance that the Hannah meter reads 4.5dkh on a 5dkh fluid, is it a linear offset? If the meter reads your seawater as 8.5, is it 9.0, or is there some factor to multiply I would need to include as dkh reports higher?