Hanna alkalinity checker reagent off again

[CTaylor]

I've been using the hanna alk checker since in came out. I buy 3 or 4 reagents at a time and put them in the fridge. I always check the last of one reagent with the beginning of the new one. The reagents are usually right on, if they're off it's only slightly. Even when they had the recall, my recalled reagents were ok....they stay in the fridge many many months maybe even a year before I get to the last bottle.....

Then I dont know what's going on with those that are getting large devations every single time and those that aren't.

 

[CTaylor]

but for somethign as important as alk, it does make sense to have a back up check every so often. I had to frag up some newer acros due to the alk swings, esp the dip I had into near upper 5's. I already keep mine ideally at 7.5. So a 1.5 loss to my corals is detrimental.

 

[zachfishman]

Titration kits can be subjective. Make sure your cuvettes are good and clean (I use kimwipes, and use the same cuvette for the zero and reagent reading to reduce variability). Using their alkalinity standard set would likely tell you if the tester is off. Of course, you'd want to test several times to average out the variability of the tester.

https://hannainst.com/hi772-11-marine-alkalinity-dkh-checkerr-hc-calibration-set.html

 

[hkgar]

but for somethign as important as alk, it does make sense to have a back up check every so often. I had to frag up some newer acros due to the alk swings, esp the dip I had into near upper 5's. I already keep mine ideally at 7.5. So a 1.5 loss to my corals is detrimental.

Like you I keep mine at 7.5-7.8 and I am very OCD about it and test virtually every day. My dKH uptake is +4/day so the dKH can dip quickly if just the smallest thing goes wrong. The CO2 regulator for my reactor decided to quit a couple days ago so I am beck to 2 part dosing (357 ml/day for alk) no dosing pumps.

I completely trust my Hanna. I do periodically double check against Salifert and Elos. Never a difference that could not be accounted as outside the margins of error. Pick the test kit you like to use and stay with it and learn to be as precise as possible each time you use it.