Large ALK reading difference between Trident & Hanna

[ReeferDog]

250 Gallon Mixed Reef System
Been using Trident for Alk, Cal, Mag readings for over 2 years.
Alk and Calcium supplemented by Kalk stirrer only, but also have (2) part to boost if the Kalk slurry gets exhausted. Currently dosing of (2) part has been turned off for one month.

Issue is my Alk (according to Trident) has been slowly trending upward from the 8-9 range where I keep it, especially after my last Kalk top-off in the stirrer, so I backed down the dosing volume of Kalk. Current Trident reading for Alk is 10.79, which I do not have confidence in. Bought fresh Hanna Alk Reagent, tested (3) times back to back this morning and got 5.9, 6.1, and 6.0.

All of my SPS look happy with normal PE and good growth. Many of the LPS corals are showing signs of stress. Torches and Frammers are losing heads, others like favia and other encrusters are showing tissue recession on edges.

All other typical values are within acceptable ranges:
CAL: 496
MAG: 1371
PH: 8.25
Temp: 78.3
Salinity: 1.025
Nitrate: 15-18
Phosphate: 0.03

Trident was calibrated with Trident solution about 1 month ago.
Going to take a water sample to LFS for another data point, but suggestions are welcome.

 

[eggie]

250 Gallon Mixed Reef System
Been using Trident for Alk, Cal, Mag readings for over 2 years.
Alk and Calcium supplemented by Kalk stirrer only, but also have (2) part to boost if the Kalk slurry gets exhausted. Currently dosing of (2) part has been turned off for one month.

Issue is my Alk (according to Trident) has been slowly trending upward from the 8-9 range where I keep it, especially after my last Kalk top-off in the stirrer, so I backed down the dosing volume of Kalk. Current Trident reading for Alk is 10.79, which I do not have confidence in. Bought fresh Hanna Alk Reagent, tested (3) times back to back this morning and got 5.9, 6.1, and 6.0.

All of my SPS look happy with normal PE and good growth. Many of the LPS corals are showing signs of stress. Torches and Frammers are losing heads, others like favia and other encrusters are showing tissue recession on edges.

All other typical values are within acceptable ranges:
CAL: 496
MAG: 1371
PH: 8.25
Temp: 78.3
Salinity: 1.025
Nitrate: 15-18
Phosphate: 0.03

Trident was calibrated with Trident solution about 1 month ago.
Going to take a water sample to LFS for another data point, but suggestions are welcome.

I trust better a Salifert test kit then the Hanna, just to make sure were your standing. After that Trying calibrating the trident with your results its better

 

[tREEFarm]

I use Hanna for nitrate and phosphate but do not trust their alk checker, which has been collecting dust for awhile now on my shelf.

I trust the Salifert alk test wayyyy more.

 

[X-37B]

I use hanna daily for the last 7 years.
Salifery and red sea are backup cross checkers.

 

[ReeferDog]

Thanks for the recommendations. My LFS tested the Alk at 6.8, so I'm leaning toward the Trident having gotten out of calibration and readings drifting artificially high.
Got another 2 month reagent supply at LFS and will use the calibration solution to rein in the Trident values. Will keep the Hanna Alk tester dusted off for bi-weekly or monthly cross checks.

Hopefully that's it. Does seem weird that all the Acros are loving the 6-7 Alk value, but the LPS are suffering. Bringing the 2-part dosing back online (slowly) to raise the alk back up.

Will report back in a few days to this thread with pics/follow up results.
Cheers - RM

 

[Randy Holmes-Farley]

Trident alk seems to be problematic with old reagents.

 

[ReeferDog]

Trident alk seems to be problematic with old reagents.

Good point Randy. So I checked the expiration dates on 3 reagents currently in the Trident and all (3) are good through November of '26. I replaced A and C, which were about empty and now the Trident calibration is running with their included calibration solution. Calibration fluids only have lot numbers on them, and not expiration dates, so no way to know what their shelf life is.
My last Trident calibration was on 7/22/25, and that was with a bottle of Calibration fluid I bought from my LFS (probably one he had left over), so I'm wondering if that was an 'old' lot, or bad batch, and caused me to incorrectly calibrate the unit 2 months ago. Will be interested to see what the next A/C/M test results are from the unit this evening. Thanks as always. - Rob

 

[eggie]

Never had issues with AlK being so off on the Trident, but I calibrate it differently

 

[ReeferDog]

Never had issues with AlK being so off on the Trident, but I calibrate it differently

You’re going to make me ask….
How do you calibrate it? I believe you can input values through Fusion from other test methods.

 

[ReeferDog]

After calibration with Trident solution and force running a test, it’s giving me a reading of 6.33, which is inline with the Hanna values in combination that I’ve turned my Versas on for dosing 2part for the last 5 hours.

 

[Reign1]

I was going to chime in on trust the Hanna .. it always is spot onwith ICP testing results .. As Randy said reagent issues ?

 

[eggie]

You’re going to make me ask….
How do you calibrate it? I believe you can input values through Fusion from other test methods.

I test with Salifert and input my values instead of the values of the bottle that come with the kits and my trident is always spot on

 

[ReeferDog]

You’re going to make me ask….
How do you calibrate it? I believe you can input values through Fusion from other test methods.

I test with Salifert and input my values instead of the values of the bottle that come with the kits and my trident is always spot on

So when I use the calibration fluid, I choose from the Task Menu>Perform Trident ACM Calibration.

I also see that going to the gear icon for the Trident tile on the Dashboard, I can do Configure>Trident and use the toggle switch for Perform Calibration. It then allows you to input values. When you upload that command to Apex, does it then run a combined test with normal tank water?

 

[eggie]

So when I use the calibration fluid, I choose from the Task Menu>Perform Trident ACM Calibration.

I also see that going to the gear icon for the Trident tile on the Dashboard, I can do Configure>Trident and use the toggle switch for Perform Calibration. It then allows you to input values. When you upload that command to Apex, does it then run a combined test with normal tank water?

Correct but dont use the Calibration fluid instead do regular water test and input those numbers, you will see the same numbers you input and then as it changes it will follow. Its the best way to keep your trident running consistent numbers for your tank

 

[ReeferDog]

So when I use the calibration fluid, I choose from the Task Menu>Perform Trident ACM Calibration.

I also see that going to the gear icon for the Trident tile on the Dashboard, I can do Configure>Trident and use the toggle switch for Perform Calibration. It then allows you to input values. When you upload that command to Apex, does it then run a combined test with normal tank water?

Correct but dont use the Calibration fluid instead do regular water test and input those numbers, you will see the same numbers you input and then as it changes it will follow. Its the best way to keep your trident running consistent numbers for your tank

Cool, thanks. One final question: Thoughts on the cheaper ABC reagents?

 

[gbroadbridge]

Thanks for the recommendations. My LFS tested the Alk at 6.8, so I'm leaning toward the Trident having gotten out of calibration and readings drifting artificially high.
Got another 2 month reagent supply at LFS and will use the calibration solution to rein in the Trident values. Will keep the Hanna Alk tester dusted off for bi-weekly or monthly cross checks.

Hopefully that's it. Does seem weird that all the Acros are loving the 6-7 Alk value, but the LPS are suffering. Bringing the 2-part dosing back online (slowly) to raise the alk back up.

Will report back in a few days to this thread with pics/follow up results.
Cheers - RM

I would suggest keeping a Salifert Kit on hand for backup readings and toss the Hanna.

The salifert reagents do not expire.

I tossed out the Hanna a while ago as their reagents only last 3 months once opened.

edit: I should clarify - Hanna Alk reagents only last 3 months when opened unless refrigerated.

 

[Reginald Reefer III]

When replacing the 'A' reagent, be sure not to tighten it completely down to create a vacuum inside of the bottle. Tighten the lid, but then back it off slightly ~1-2 turns. Root cause is not enough reagent 'A' is being injected and you get very skewed readings. Same thing goes for the other reagents. My readings were all over the place and that's what solved it for me.

 

[eggie]

Correct you will see the same numbers you input and then as it changes it will follow. Its the best way to keep your trident running consistent numbers for your tank

Cool, thanks. One final question: Thoughts on the cheaper ABC reagents?

They work good as well. That's what I'v been using

 

[areefer01]

Trident alk seems to be problematic with old reagents.

That seems like an odd statement to make. Is this your experience in using one? Reagents have exp dates. Long time Trident ACM user and have not run into that issue. Doesn't mean it can't happen but not sure I would agree with this statement.

Typically you run a calibration 48 to 72 hours after reagent A, B, and C swap as noted by Neptune. This gets a couple tests in and lets things settle. Swapping only reagent A, Alk, is not necessary since they are the same lot numbers. In most cases.

 

[painter1982]

My Hanna checker is same as icp test results. I fill the vial up until the bottom of the water in center is on the 10ml white line. Then add the reagent. Rotate 10 times and flick out bubbles then check.