Help! Hanna Alk Checker

Albertan22 · Apr 17, 2020

So I just opened up my first new reagent for my Hanna Alk Checker. I had one more test in my original bottle so ran that first and got a result of 9.2 which is what I expected. I used the new reagent and got 8.4! I re-ran the new reagent and got 8.6. I had ordered two bottles of new reagent so opened up the second bottle which was the same batch number as the other new one and it ran 8.5. My Salifert test is reading 9.0.

What would you do in this situation? Order more reagent not knowing if you’re going to get the same lot number? Or just use the new stuff with a new stability target of 8.5 instead of 9.2?

LiveWire · Apr 17, 2020

Send Hanna an email or give them a call. I am sure they will be happy to help you figure out whats going on.

Contact Us

Contact us with questions about our products or if you need technical assistance, or would like to speak to your local Hanna Instruments office.

www.hannainst.com

Albertan22 · Apr 17, 2020

LiveWire said:
Send Hanna an email or give them a call. I am sure they will be happy to help you figure out whats going on.

Contact Us

Contact us with questions about our products or if you need technical assistance, or would like to speak to your local Hanna Instruments office.

www.hannainst.com

I just sent an email but got 3 auto replies back that their office was partially **** down due to covid and they hope to be back to normal soon

ReefnFG · Apr 17, 2020

This actually just happened to me also. So they give 30mls in the bottle, but you are only supposed to do 25 tests, so you don't want to use all the reagent (which I also just learned). The reagent also doesn't last that long after being opened probably no more than 2-3 months. So what I started doing is marking the reagent bottle after I complete a test and when it was opened. This way I can track how many tests I used it for and how long.

Between the variation in testing I'd say the values are close enough to go with the new Hanna readings. Salifert test is good but introduces more human error trying to figure out the exact point the color changes than the Hanna checker does.

PatW · Apr 17, 2020

There can be variation from reagent bottle to reagent bottle. You could make a standard ALK solution to test against on each new bottle. When I am coming to the end of a reagent bottle I test the tank with both the old and the new to get an idea of the possible difference. Usually, they are close enough to each other that it is no big deal.

Albertan22 · Apr 17, 2020

PatW said:
There can be variation from reagent bottle to reagent bottle. You could make a standard ALK solution to test against on each new bottle. When I am coming to the end of a reagent bottle I test the tank with both the old and the new to get an idea of the possible difference. Usually, they are close enough to each other that it is no big deal.

This is exactly what I did but they were 0.8 dkh apart which seems pretty wide doesn’t it?

piranhaman00 · Apr 17, 2020

Stability is key

just shoot for the new alkalinity you have.

Yes frustrating

Albertan22 · Apr 17, 2020

piranhaman00 said:
Stability is key just shoot for the new alkalinity you have.

Yes frustrating

Yeah I was thinking of doing that, just use the new number as my target. I might just do a few more tests to make sure the reading is consistent then run with it.

Albertan22 · Apr 17, 2020

So I just got a reply back from Hanna and was told that for an expected reading of 9dkh, the error for the HI772 tester would be + or - 0.75dkh so the reading is within tolerances. They’re going to check with their production group for issues with the specific lot still though. That range of error is a bit of a wake up call though for those of us who try to keep rock solid numbers. I guess maybe we expect to much from hobby grade kits.

PatW · Apr 18, 2020

Albertan22 said:
This is exactly what I did but they were 0.8 dkh apart which seems pretty wide doesn’t it?

Most of the time, the difference is .1 or .2. The biggest I have seen is .4. But .8 seems possible.

Nathan Milender · Apr 30, 2020

I recently had trouble with this as well. It appeared to happen slowly and I titrated down my carb over several weeks. Eventually ran out of reagent, got a new bottle, DkH was suddenly down 1.5 from where it normally sits (or I thought it sits). Did anyone get confirmation that the number fails to a lower than expected reading as time goes on? Also, thanks for the tip on the 2-3 months. If you check 1/week a bottle can last 6 months and then be full of error.