Alkalinity testing. Red sea and Hanna do not agree

[bdejong1112o]

I have the hanna checker for alkalinity and tested it against the red sea alkalinity test that came in my basic reef kit. The issue is that they do not agree with eachother, at all. I tested it twice tonight and here is what i am getting.

Red sea - 8.57Dkh (Used the 1Dkh resolution method)
Hanna - 11.4Dkh

I ran it twice and both came up with the same answer. I must be missing something or screwing it up.

Just for background.
Amonnia 0
Nitrite 0
Nitrate 20

 

[Diesel]

That is a big difference.
Can be a user error or old regent even the test kit are new.
I used with the hanna three different regents and came out with different results just not as large as yours.

 

[bdejong1112o]

In did check the expiration dates in both kits. All are at least wellnwithin thier expiration dates.

I repeated the tests twice and am about to do it again because this is just way to big of a difference.

 

[Kyle Rinker]

Just a thought--are your vials for the Hanna checker clean and free of finger prints? Any residue on the outside can dramatically skew the results. Or, have you by chance left the reagent in the vial for an extended time after a prior test? The reagent can discolor the glass and skew the results.

 

[bdejong1112o]

ok, hand in the air. It was me. Read the chart wrong. Both are reading the same thing. Ugg, hate it when I mess up. Especially when I used the wrong one to raise alkilinity. I assume its not so high as to bother anything? Only a few cardinal fish, one GSP colony and some zooanthids.

 

[Diesel]

You know that Hanna had a few recalls on their regents even the dates were still good for a year or so.
Yet, I'm using Hanna test every day and I double check with Redsea once a week.
And yes there is a difference but it ain't that much off

 

[bdejong1112o]

See, this is why I need simple show me a number style testers. LOL..... Counted the drops right but used the third coumn of numbers whick looked like drops but were actually the Dkh values for the number of drops on the far left. Oops, life goes on.

 

[Diesel]

ok, hand in the air. It was me. Read the chart wrong. Both are reading the same thing. Ugg, hate it when I mess up. Especially when I used the wrong one to raise alkilinity. I assume its not so high as to bother anything? Only a few cardinal fish, one GSP colony and some zooanthids.

Glad you figure it out my friend.
Both are solid test kits but yes mistakes happen to all of us.

 

[bdejong1112o]

Yeah, I really screwed the pooch on this one. I was setting up to do the tests again and looked at the test instruction card and had a real life face palm moment. Hated to admit it but it was all me....

 

[Diesel]

Yeah, I really screwed the pooch on this one. I was setting up to do the tests again and looked at the test instruction card and had a real life face palm moment. Hated to admit it but it was all me....

Ah and here you have it, the nick name found you as it happens to many so many times.
The Facepalm reefer" congrats

 

[Jongalt26]

In this case it may have been you however i have had issues with the hanna alk checker. I was dialing in a calcium reactor and was using the hanna to test daily. I have, had rather, numerous acans and they wouldnt open up. Assumed it was alk swings. Finally got it dialed in at 8.4 dkh but they still didnt open back up. Started chasing PO4 since the reactor adds PO4 to the tank, still no luck. It occurred to me i needed to verify my test so i used red sea. Turned out my alk was at 7 dkh fo red sea yet hanna was 8.4. Snagged a salifert kit to find out which test was correct and it confirmed the red sea was correct.
I still use the hanna check just because of the resolution is better and im just checking for variations and i dont have to rely on color change but until i order a set of calibration standards I can't rely on it for an accurate measurement.