Alk Testing with AFR (Hanna vs Hydros IV)

[crabgrass]

I am slightly confused on the results I am seeing between two different devices. I am also not sure if the nature of ARF (how its metabolized, etc) is throwing stuff off as well.

At one point, my Hydros IV and Hanna Alk checker were both reading 8.3-8.5.

My IV has drifted to 9-10, however Hanna is still reading Alk in the 8.3 range.

• I recalibrated Hydros IV PH and cleaned everything - still reading in the low 10's
• Hanna is steady at 8.3-8.5

I know AFR metabolizes in reef tanks differently and isn't always detectable through traditional means. Are the two different testing mechanisms detecting it differently? I also know Hanna is consistent, but not always accurate. So a 8.5 reading could really be 9.5 or a 7.5.

My Hanna meter is 2 years old and has some wear and tear. The Hydros is pretty new (couple months with a new PH Probe). To throw things off even more, Red Sea Pro Alk testing has it in the 7's

 

[Randy Holmes-Farley Verified Community Expert]

I don't see any reason for the AFR to play a role.

That said, i do not know why they would read differently, and which, if either, is more accurate.

 

[kathouqc]

Did you find your issue?

I have a 4 Month old Alk Hanna tester and I read 9 Dkh,and on my new hydros x10 with IV I got around 10-12 Dkh,that wierd.I will retry to calibrate the PH probe maybe is my problem

 

[crabgrass]

Sort of, maybe

I ended up doing tests with Red Sea, Salferit, Hydros and Hanna.

The Salferit and Hanna matched consistency. My probes were properly calibrated before. So I increased the reagent concentration so my hydros aligned with Salferit and Hanna. There are some posts or coralvus site on how to do this as well. You can actually use the CoralVu (diluted) reagent with Salferit tests interchangeably it looks like to validate.

Red Sea would consistently be 0.5+ readings on all.

So, I can’t say which test is right or wrong, but I tried to align my hydros to Salferit, so I had a baseline for consistency.

 

[n2585722]

Sort of, maybe

I ended up doing tests with Red Sea, Salferit, Hydros and Hanna.

The Salferit and Hanna matched consistency. My probes were properly calibrated before. So I increased the reagent concentration so my hydros aligned with Salferit and Hanna. There are some posts or coralvus site on how to do this as well. You can actually use the CoralVu (diluted) reagent with Salferit tests interchangeably it looks like to validate.

Red Sea would consistently be 0.5+ readings on all.

So, I can’t say which test is right or wrong, but I tried to align my hydros to Salferit, so I had a baseline for consistency.

Also make sure you do not have bubbles in the reagent line. Also if the pH probe is too low in the beaker it will read high on the testing. This is where mine is set in the photo.