HI772 bad results

[kenchilada]

I have a brand new HI772. I used it for the first time last night on a new 215G tank filled with Fritz blue box, so was expecting a dKH around 8. Instead it read 3.2dKH. I repeated the test and got 3.3dKH. I thought maybe I had a bad batch of salt but didn’t trust the result.

I went to the LFS today and bought an AquaForest alkalinity test. The result was 7.8dKH. I tested with the Hanna again and again got 3.2dKh. I’ve read the directions 100 times, not much to get wrong. Any ideas?

 

[Shirak]

First time using a Hanna alk meter?
Can you list all your steps?

 

[kenchilada]

First time using a Hanna alk meter?
Can you list all your steps?

10mL sample water, cap it, clean glass and tap to remove bubbles, put in checker, close lid, press button till C2, remove and add 1mL reagent, cap, invert 5x, clean glass, put in checker, close lid, press button, get incorrect result, cry about it on the internet.

 

[Shirak]

Hmm.. Not sure if it matters but I turn on wait for C1 then insert and press button after cleaning all fingerprints. Then add reagent etc.. make sure clean again. Reinsert in the same orientation. I have a small mark on my vial so I know it's always pointing in the same direction between steps.

Could be bad reagent? Or bad checker?? Did you swish the reagent around a bit first if it's brand new off the shelf? If you have a second vial try that too.

Yeah.. I don't think it's possible to have 3.2dkh..

 

[Shirak]

dkh of around 8 should be pretty noticeable blue color after adding reagent and mixing.

 

[Shirak]

Can you redo the test and post a photo of the vial after mixing with reagent against something white? Might help determine if it's the reagent or the checker.

 

[kenchilada]

It’s bad reagent that came in the kit. Not expired (02/2022). I bought a new reagent at the LFS and it reads 8.5dKH.

New reagent...

The bad reagent is on the left, new on the right...

Feels bad!

 

[Skynyrd Fish]

Good you got it sorted out.

 

[Shirak]

Glad you figured it out! I would contact Hanna and ask for a bottle of reagent!

 

[kenchilada]

Good you got it sorted out.

Now the big question is... is 8.5dKH correct or is the AquaForest 7.8dKH correct? ;Nailbiting

 

[vetteguy53081]

safe range is 8-9. Youre not far off either way

 

[Skynyrd Fish]

I hate to say, I’m a Salifert dkh person. I would consider using the tester as a trend watching device. If everything looks good at 8.5 keep it there with dosing. Keep a log or journal. You can send an ATI water test and compare the results also.

 

[kenchilada]

I hate to say, I’m a Salifert dkh person. I would consider using the tester as a trend watching device. If everything looks good at 8.5 keep it there with dosing. Keep a log or journal. You can send an ATI water test and compare the results also.

Yeah I’ve used Salifert since the 90s, thinking I’ll sell this and go back. I find myself “going back” a lot lately. I used to buy 4-5 kits, combine the reagents, test against a homemade standard and write the correction factor on the bottle.

I’ve never had a cheap test kit be off this badly. For $50 it should be dead on.

 

[WallyB]

Now the big question is... is 8.5dKH correct or is the AquaForest 7.8dKH correct? ;Nailbiting

The Hanna Alk Tester will usually be off by 0.5 dkH vs a Salifert, but it varies.
Remember the specs on the Hanna is +- 0.5 dkh Accuracy.

I've tested both to death since I built a Alk Monitor using the Hanna Egg.

I bought Alk Reference Solution and even made my own when I had a proper Salt water mix.
Both tests kits are good, If the regeant is not too expired, or contaminated.

What you really care about is consistancy of your test results to achieve Tank ALK Stability, and both Hanna and Salifert will get your that from a test result. Salifert maybe a bit more consistant.

I do test with both kits to double check every so often.
The Hanna is automated runs once a week, or when I away from Home and sometimes I test with the Salifert Kit before making dosing adjustment.

This table off my Hanna Alk test will give you an idea between the two tests.

The (number) in the Bracket on the Salifert Column is the difference between that Hanna Alk and the Salifert Hand Test.

Here are the results from my other Tank

If you are curious how I turned a Hanna Alk Egg Tester into a 3 Tank Alk Monitor.

https://www.reef2reef.com/threads/★-diy-auto-★-alkalinity-monitor-★-3-tank-hanna-with-raspberry-pi-ardiuno-with-advanced-features.689106/

 

[windemerejack]

IMO you should never use 2 test kits to test the same thing, it will drive you insane as they will never agree with each other, or very rarely.
Its best to stick with one you like and get a known standard and test it to see what it reads and if needed adjust things.
If it reads 8.4 and the known solution is 8.6 then you know your reading is 0.2 out, so if your normal test shows 9.1, you know its actually 9.3.
You are chasing consistency rather than actual numbers, these are hobby grade test kits and as such will have a degree of inaccuracy.

 

[Scdell]

Huh! I've been on here complaining about Hanna Alk reagents for a while now. All I get in response is bad procedure on my part. Well....... Here's proof!

 

[windemerejack]

Huh! I've been on here complaining about Hanna Alk reagents for a while now. All I get in response is bad procedure on my part. Well....... Here's proof!

didnt you know that Hanna test kits are never wrong? or that for £70 you are getting Lab grade test kits which would normally cost thousands?
It is always the users fault

It always makes me laugh when people say i think my hanna tester is a bit out im going to compare my hanna to my salifert test kit, surely this proves that salifert is better than hanna.

 

[Scdell]

didnt you know that Hanna test kits are never wrong? or that for £70 you are getting Lab grade test kits which would normally cost thousands?
It is always the users fault

It always makes me laugh when people say i think my hanna tester is a bit out im going to compare my hanna to my salifert test kit, surely this proves that salifert is better than hanna.

Thank you!!!!
I was beginning to think I was nuts. I did buy a Salifert to compare with my Hanna. Salifert is real close to the ICP test. Hanna is a good .7 over both. For an important value as DKH they should be much better than what they are. And I strongly feel Hanna has been having reagent issues with alk for a while now. Some are way off some are kinda close.
I'm guessing all these people spend $50 on their tester and they think they're getting a precision tester. It has to be for that price, right?

 

[windemerejack]

I keep saying the Hanna checkers are no more accurate/consistent than salifert, red sea, or most other top branded test kits, they only come in to their own because they have a digital read out. They are only worth the expense if you find it hard to match colour/colour change, if you can judge them quite easy then there is no need to spend that amount on a Hanna kit.
If you want a really accurate test kit then you need to look at lab grade test kits worth £100's and £1000's.

 

[Scdell]

I keep saying the Hanna checkers are no more accurate/consistent than salifert, red sea, or most other top branded test kits, they only come in to their own because they have a digital read out. They are only worth the expense if you find it hard to match colour/colour change, if you can judge them quite easy then there is no need to spend that amount on a Hanna kit.
If you want a really accurate test kit then you need to look at lab grade test kits worth £100's and £1000's.

OMG, the grief I've gotten for not standing on my head and holding the vial between the right two toes while testing. People think this is a lab grade instrument. The process they go through to test. If you don't follow their exact procedure, you're never going to get a correct reading. It's certainly nice to hear from someone with sense on this.