hey guys! Heres a little backstory. I had an unopened and sealed bottle of Hanna Checker Alkalinity reagent and have been testing between 7-6.5 DKH, so i was out of town and ordered a new bottle as i finally used most of the last one up, I finally tested my alkalinity with the hanna checker using the old reagent and new reagent. the old read 6.5 dkh which is around what it was reading before. but heres the crazy part! the new reagent read 11 dkh!!! now that blew my mind because i was maybe expecting it to be off by like 0.5-1dkh but almost 5 dkh was a lot! so i also have the red sea test kit and tested it with that and got 10.5 dkh which is pretty close the 11DKH i got from the hanna checker (i dont expect perfect readings between the two as theyre two different testing processes but theyre close enough). so the old hanna reagent i had must have been a bad batch because i never got a reading above 7 dkh at any time throughout using the bottle. so Just wanted to give you all a little tip to every now and then double check your readings with another test kit because you may be surprised!
**Tip** Double Check your test kits
- Thread starter Mikedawg8898
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Daniel@R2R
Living the Reef Life
YES! Good PSA! Thanks!
ReefnFG
Community Member
I actually just experienced something similar to this. Although it wasn't anywhere near the difference you saw, I probably had 5 or more tests left of reagent, but something was telling me to try new reagent. After switching to the new reagent and comparing, I found the old reagent was reading 1 dkh higher (read 7.5, new reagent read 6.5) This was concerning due to me transitioning the tank to SPS. I also checked the Hanna checker with their calibration cuvettes and it was right on. So today I will be purchasing a Salifert alkalinity test kit and Hanna Alkalinity reagent backup just as a sanity check. Also I will no longer be using reagents till they are empty and keeping a closer eye on how long they have been open (this will require some experimenting and research to see what kind of shelf lives these have after they are opened).
homer1475
Figuring out the hobby one coral at a time.
You guys also have to realize there is 30ml of reagent in the bottle, but Hanna only claims 25 tests(25ml used).
Since I started marking my bottles, and only using the stated 25 tests, my reading between bottles is much more consistent.
Thats not to say different batches of reagents can be bad. Check lot numbers and expiration dates.
Since I started marking my bottles, and only using the stated 25 tests, my reading between bottles is much more consistent.
Thats not to say different batches of reagents can be bad. Check lot numbers and expiration dates.
ReefnFG
Community Member
It's a valid point you bring up about it containing 30mls. It's one that kind of got pushed to the side but I will definitely be monitoring that better. Still kind of weird that the results leading up to that point were similar (+- 0.2 based on my testing schedule, which is not everyday probably more like 2 times a week).
Are you aware of an approximate time that the reagent should be used after it has been opened, assuming its stored properly?
Are you aware of an approximate time that the reagent should be used after it has been opened, assuming its stored properly?
