Hanna Alk checker reading higher?

[SifuMemphis]

I've always used the Hanna checker to sanity check the alk with my trident, but today when I swapped out my trident reagents (Calibration done), I noticed that my alk reading was 7.2 on the trident, but 7.6 with my alk hanna checker.

The Trident calibration solution that came with it shows 8.1 Alk, 430 Calcium, and 1260 Mag. Since it seemed that my alk checker was reading higher, I took 10ML from the calibration solution and ran that through my Hanna checker as well. The reading came back 8.6 (.5 higher as well)

I am aware that the calibration solution is suppose to be accurate, but in this case, which would you trust? I'm aware that Hanna is considered hobby grade, so I am leaning towards trusting the calibration solution / my Trident reading.

If my alk checker is off, is there a way to recalibrate the hanna checker? If not, is the unit just broken and SOL?

 

[reefdoink]

The Hanna checker has a tolerance of accuracy.

Accuracy @ 25°C/77°F

±5 ppm ±5% of reading

 

[SifuMemphis]

Well, that makes sense then. It's def reading .5 higher. Thanks Reefdoink

 

[OREGONIC]

Hanna seems to be slightly inconsistent between bottles of reagents. I have made a habit of as I am nearing emptying a bottle of reagent I open the new bottle and have a few nights where I test with old reagent then new reagent. If I get 2-3 nights of this overlapping testing I get an good idea of how different the new bottles tests from the previous. I have had reagents that were up to .5 different but usually it is just .1 - .3

 

[Rubberfrog]

Edit: see response below

 

[homer1475]

Expired test kits and uncalibrated probes. Those results have no value.

What?

Did you read the OP?

Freshly calibrated trident, and a brand new bottle of hanna reagent. No probes involved or expired test kits.

 

[Rubberfrog]

What?

Did you read the OP?

Freshly calibrated trident, and a brand new bottle of hanna reagent. No probes involved or expired test kits.

I don't know what I read. I'm not even hungover. I don't know how I got this so wrong. I swear I thought I read something about buying a used apex/probe setup.

I think I was reading a different thread and accidentally clicked one of the links below it.

 

[homer1475]

Been there done that. lol