Hanna Checker dKH problem? Got Zero reading

[Haacheew]

I have used Hanna Checker dKH without problem for the past 7 months. But yesterday, I got 0 (zero) reading from numerous tries.

I checked battery with meter, cleaned test tubes inside out to make sure no grease or finger prints. Then, performed test 6 times on tank water, also performed many times on fresh mixed saltwater. ALL came to the same ZERO reading. Any idea or help?

 

[ndrwater]

Is the reagent expired?

 

[Haacheew]

Is the reagent expired?

hmm, it shouldn't be because I bought the set 7 months ago. But, it is a good point.

 

[NYCMAN]

there is a calibration fluid that is sold by Hanna that verifies if your checker is working. It does not calibrate, just lets you know if it is working (meaning measuring within a decent range of error).

 

[Haacheew]

I tested water again today. Got ZERO readings from all 3 tries; same as 9 days ago.
So, I opened a brand new bottle of reagent and got an average 7.9 dKH reading from 3 tries.

It is so weird. As you can see from the photo, both older and newly opened bottles have the same EXP:10/2020.

 

[saltyhog]

Was the reagent giving the zero readings green like the other one? That's really weird. An incorrect reading is not terribly surprising but 0.0 is out there.

 

[Haacheew]

Yeah, it is wierd. I performed 3 tests with the "older reagent" all got ZERO readings. But, as soon as I used the newly opened bottle of reagent, I got 3 readings closed to 8dKH. I noticed the "older reagent" color is not as green as the "newly opened reagent".

 

[Dannyboy402]

Mine has been doing the same thing as well. I should get a new bottle of reagent.... Sucks that the reagents don't last very long. I've just been using my salifert test in the meantime.

 

[juniorgomez708]

I just experienced this with mine. Tested 5 times and every time I got zero. I barely used my reagent a few times. I did notice that the liquid is not as blue or green as well. So does this mean that even though it’s not expired, it’s most likely that they don’t last long?

 

[Dannyboy402]

I just experienced this with mine. Tested 5 times and every time I got zero. I barely used my reagent a few times. I did notice that the liquid is not as blue or green as well. So does this mean that even though it’s not expired, it’s most likely that they don’t last long?

Yeah I bought a new bottle of reagent and it started to read correctly. The reagent for this test doesn’t last long.

 

[mdb_talon]

Countless stories on here about how bad the hanna alk reagent is, but this is first i ever seen of it reading 0! I guess the good thing is at least it was off enough to know without a doubt it was not working.

 

[Haacheew]

As soon as you "open" the seal, it will lose efficacy rapidly, even before the expiration date. See my above posts, both bottles had the exact expiration date. The "opened" bottle had lost all its efficacy.

 

[EricR]

Weird. I'll have to watch out for this.
I wonder what the length of time you have after opening before the readings start getting inaccurate.

Like noted in post #11, at least at 0 dKH, I'd know the test was invalid.
If it just starts gradually decreasing, I'd probably trust it and do something stupid to my tank.

 

[Haacheew]

Weird. I'll have to watch out for this.
I wonder what the length of time you have after opening before the readings start getting inaccurate.

Like noted in post #11, at least at 0 dKH, I'd know the test was invalid.
If it just starts gradually decreasing, I'd probably trust it and do something stupid to my tank.

In my case, I opened the first bottle, then got zero ready after 7 months. See Post #3.

 

[gbroadbridge]

I have used Hanna Checker dKH without problem for the past 7 months. But yesterday, I got 0 (zero) reading from numerous tries.

I checked battery with meter, cleaned test tubes inside out to make sure no grease or finger prints. Then, performed test 6 times on tank water, also performed many times on fresh mixed saltwater. ALL came to the same ZERO reading. Any idea or help?

The LED or photo transistor is either blocked or failed.

With the lid open, do you see the LED light up when you press the button at the C1 prompt?

edit: Sorry didn't see you were using very expired reagents.

Even if they worked, the readings would be very suspect.

A bottle barely lasts me 3 months

 

[Lasse]

There is a way to hinder the Hanna alk to show lesser and lesser dKH (or ppm for that meter) with age of open reagent bottle. I had the same story - my reading decrease from a new open bottle with time. Double check with another method show that there was not a real decrease - only that the reagent did not give the colour it should. Comparing with a fresh newly open bottle confirm the false readings of the old reagent. I did a test with shaking the bottle every time I use it - not better result. After this I start to store all open bottles in my refrigerator and voila - it works and give the right readings all the time. I have tested this for 1/2 a year now and comparing with other types of measurements - the last bottle is now 4 months old (open) and still give the same result as my other tests (and a brand new opened bottle)

My findings - Store the open reagent bottle in a refrigerator, shake before use, It works with the cold reagent directly taken from the refrigerator

Sincerely Lasse