Hanna alkalinity calibration?

[Sophie"s mom]

Good morning everyone! So I discovered last night that my Hanna alkalinity checker is way off. I have ordered the calibration kit from BRS, but my question is how often do these need to be calibrated? I have been using it for a few months now, I am attempting to get dosing right so I can hook up an auto doser. Well last night when I checked it was 7.8! The night before it was 8.2 so in the morning yesterday I added some C Balance part B. That should have raised it slightly not lowered it. This made me check it against my Salifert kit, which read 11.2, I have always trusted my Hanna kits completely, but had no idea they needed calibration.

 

[elysics]

Good morning everyone! So I discovered last night that my Hanna alkalinity checker is way off. I have ordered the calibration kit from BRS, but my question is how often do these need to be calibrated? I have been using it for a few months now, I am attempting to get dosing right so I can hook up an auto doser. Well last night when I checked it was 7.8! The night before it was 8.2 so in the morning yesterday I added some C Balance part B. That should have raised it slightly not lowered it. This made me check it against my Salifert kit, which read 11.2, I have always trusted my Hanna kits completely, but had no idea they needed calibration.

When they say calibration, they mean the technical term. It just tells you the number it should be and the number the checker actually spits out, it doesn't actually make any setting adjustments on the checker to make the difference disappear.

It basically tells you whether the led is still working correctly and if it doesn't you might change batteries or complain to Hanna to get a new one under warranty, that's all it does. To use the "calibration" you need to write that down and make the correction calculations yourself.

The much more likely problem with the results comes from the reagent, not from the checker, and to find that out you need an alkalinity reference liquid that you run a full normal test as if it were tank water.

 

[Mr. Mojo Rising]

So why is hanna wrong and salifert is right? Not arguing, just wondering how you come to this conclusion.

How do the corals look?

 

[eliaslikesfish]

So why is hanna wrong and salifert is right? Not arguing, just wondering how you come to this conclusion.

How do the corals look?

hanna>salifert all day every day for me

 

[elysics]

hanna>salifert all day every day for me

If you checked at the beginning of opening the salifert test that the numbers are right o would trust the salifert more than the Hanna. The salifert solutions
(just talking about the alkalinity test) won't really go bad unless you leave the lid open a long time. The Hanna one will go bad.

In either case though, you should have a reference solution on hand and check the tests, especially if they disagree, not trust them out of the box.

 

[eliaslikesfish]

If you checked at the beginning of opening the salifert test that the numbers are right o would trust the salifert more than the Hanna. The salifert solutions
(just talking about the alkalinity test) won't really go bad unless you leave the lid open a long time. The Hanna one will go bad.

In either case though, you should have a reference solution on hand and check the tests, especially if they disagree, not trust them out of the box.

huh?

 

[Sophie"s mom]

So why is hanna wrong and salifert is right? Not arguing, just wondering how you come to this conclusion.

How do the corals look?

Coral look good, but I went with that assumption because the C Balance always raises the alk, never lowers it. But indeed is just an assumption on my part

 

[eliaslikesfish]

Coral look good, but I went with that assumption because the C Balance always raises the alk, never lowers it. But indeed is just an assumption on my part

did you try testing it a third or fourth time with the same result from the hanna?

 

[Sophie"s mom]

did you try testing it a third or fourth time with the same result from the hanna?

Not yet, today when I get home from work I will do that. As well, I will change the battery and try again. It never occurred to me that a low battery would give an off reading either. I will post what I come up with . Thank you to everyone helping me with this.

 

[DanyL]

I think your assumption that the Hanna lies is likely to be true according to your observations, and like mentioned above I would first try and replace the reagents.

The calibration fluid they sell is in fact a reference of a known value which you can compare with the result, you can’t actually calibrate their checkers with it unfortunately.

An easy way to determine which test lies is to mix a fresh batch of saltwater with known parameters and test it, this works great for most parameters if the salt is consistent and can be trusted (for example Red Sea’s salt comes with an ICP test serial number you can log in to their site and compare against it).

Hanna’s Alk reagents indeed are more likely drift over time than Salifert - but both can be wrong, so make sure you know which one it is.

 

[elysics]

huh?

What's your question? My point is I wouldn't trust either out of the box without running a reference, but if I knew the same bottle of the salifert test was spot on in the past I would trust salifert more than Hanna

And the calibration kit Hanna sells doesn't test the most important part, the reagent.

 

[taricha]

Interestingly, I've found that common alk tests are usually consistent - but don't usually agree (not highly accurate).
Which means that most any common alk test is fine for maintaining consistent alk (important) but not great at nailing an exact number (pretty un-important).
If you want an actual calibration of an alk test (hanna or otherwise) you need to measure against known alkalinity solutions.
@Dan_P has done this for his hanna alk here...

Hanna Checker. When I compared my Hanna Checker alkalinity measurements to the amount measured by titration, the Checker results were consistently higher (post #170). To correct the Checker readings, a calibration curve was generated with a sodium bicarbonate solution and titrated aquarium water. Note how well the Red Sea titration performs.

 

[DanyL]

Interestingly, I've found that common alk tests are usually consistent - but don't usually agree (not highly accurate).
Which means that most any common alk test is fine for maintaining consistent alk (important) but not great at nailing an exact number (pretty un-important).
If you want an actual calibration of an alk test (hanna or otherwise) you need to measure against known alkalinity solutions.
@Dan_P has done this for his hanna alk here...

I agree, however a difference of >3dKh does indicate a faulty result in one of the tests, and I wouldn’t attribute this to the generally low accuracy of all home test kits.

 

[eliaslikesfish]

What's your question? My point is I wouldn't trust either out of the box without running a reference, but if I knew the same bottle of the salifert test was spot on in the past I would trust salifert more than Hanna

And the calibration kit Hanna sells doesn't test the most important part, the reagent.

oh ok i see what you’re saying, I was confused by your wording before.

 

[Sophie"s mom]

So why is hanna wrong and salifert is right? Not arguing, just wondering how you come to this conclusion.

How do the corals look?

Turns out your question seems very valid. I did multiple tests today when I got home. 2 back to back with Hanna got same results 7.3. Changed battery and tested again, still got 7.3. Switched to Salifert, tested twice, got 11.2 both times. Lastly went to API, and got 7. So I am assuming I need to add some C balance to slowly bring it up. Does this make sense to you? 2 corals have issues, the only acro I have has not been great for awhile. Color is good but not much polyp extension. And toadstool has been closed a couple days now, but it does appear to have glossy coating so it may just be trying to shed. Lights are off now so can’t really get pictures.