Hanna Alk Reading Low, can I just scale it?

[MarsReefer]

I got a new batch of Hanna Alk reagent and it is reading significantly low. I always do an initial test on my salt water storage, which should read about 12.2-12.5 freshly mixed. The current batch of reagent I got is reading 9.3.

Is there any way to fix it or do I just need to toss the bottle and buy another one?

Does anyone know if the reading is linear across the scale? Can I just add 3 to my reading across the board? My tank is reading 5.5 when it usually reads 8.3-8.6 so it looks pretty linear, but i'm not sure if that is just a coincidence or not, and if that trend will hold at lower levels.

 

[gfox]

I would complain to Hanna.They should replace them.

 

[mike550]

@MarsReefer sorry for the late reply. Im trying to find an old post that talked about how the Hanna Alk reagent would go bad and start causing low readings. As an example, my reagent was opened mid January and kept in the refrigerator. Today (so maybe 60 days from when I opened it) my Hanna checker read 6.6. I tested with a Salifert titration test and measured 8.6

Just found the thread

Thread 'Important findings according how to store open bottles of the reagent for Hanna Marine alkalinity checkers'
https://www.reef2reef.com/threads/i...-for-hanna-marine-alkalinity-checkers.893762/