HI 755 Hanna Alkalinity Checker Powder Reagents Replaced with Liquid

by • December 4, 2010 • Test KitsComments (0)2137

Ever since the HI 755 Hanna Alkalinity Checker came out, a lot of reef enthusiasts have been complaining about the inconsistencies of the testing results. I’ve experienced this fist hand on my review where the reagents that came free with the checker marked ‘LOT 1‘ was reading higher than the newer reagents marked ‘LOT 3.’ Several folks from different forums were experiencing the same thing which prompted Hanna to update their instructions by shaking the cuvette for 2 minutes rather than 30 seconds.

On November 11 at Hanna’s Sponsor Forum at Reef Central, they announced the following:

To Hanna Instruments HI755 customers:

During the past 3-4 weeks, we have been analyzing various solutions for improving the process of the HI755 alkalinity checker.

We are pleased to announce that we have reached a solution that will both improve the procedure, and enhance the accuracy of the checker over a wider range of alkalinity levels.

The solution involves replacing the HI755-25 powder reagents with HI755-26 liquid reagents. The performance of the liquid reagents was benchmarked against the results of an automatic titrator in seawater aquarium samples. These repeated tests showed consistency in performance within our original accuracy specifications of (+/-5% of reading, +/- 5 PPM.

In addition, the measurement time has been reduced to less than 30 seconds because the liquid reagents do not possess the same solubility issues as the powder reagents.

Our plan is to offer a free upgrade kit to all of our customers. The kit will include the liquid reagents, a new revision of the instructions, and some spare caps for the cuvettes.

To receive your kit, please go to www.hannainst.com/reagentupgrade and provide the required information. The upgrade kits are being produced as we speak. Our goal is to begin shipping them beginning the week of 11/29/10.

Thank you for your continued feedback and support.

Hanna Instruments Management Team.

I’ve filled up the upgrade form and currently waiting for the replacement liquid reagents to arrive. I just hope they will still work even if they come frozen due to the freezing temperatures now in the US and across the globe.

Request for your liquid reagents now.

Update #1: Just heard from Hanna (Dec. 6, 2010):


Thank you for your concern. The liquid reagents will still have a shelf life of several years.

As far as the freezing temperatures, this is something we take into account, as we make hundreds of liquid reagents and solutions. There should not be any adverse effects from being frozen and thawed.

Thank you.

Sounds good!

Update #2: Just heard from Hanna again (Dec. 13, 2010):

Hi Reggie,

Thank you for your continued support and interest in our products. Recently you registered on our site to receive an upgrade kit for your HI 755 Marine Alkalinity Checker. We have started shipping the upgrade kits today, and we expect to have completed shipping by Wednesday.

Since you have provided an email address, you will be receiving a notification from UPS with your tracking number. If you have not received a tracking number by Thursday, please let me know.

The Kit includes:

1. Additional cuvettes and caps.
2. New liquid reagents and a syringe.
3. A modification to the instructions to account for the incorporation of the liquid reagents.

Our research and development team conducted numerous tests and determined liquid reagents produce more accurate results over wider alkalinity ranges. In addition, we have reduced the measurement time to less than 30 seconds because the liquid reagents do not possess the same solubility issues as the powder reagents

As always, please contact us at any time for any questions or feedback.



Update #3: UPS tracking number sent via email (Dec. 13, 2010)

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