"old" reagents ... Specifically hanna alk solution

[BryanM]

I would interpret as 10.7

The Marine master alk test has accuracy +/- .3 dkh so if the water is truly 10.7 then you could test multiple times and get readings anywhere from 10.4-11 and it would be within spec for that test kit.

That's fair, the tests were over a 2 week period tho, and kept rising.

Service folks tested it at 9, and new reagent is testing in the same area.

 

[JonasRoman]

Old is in quotes because its not even a year old.

But basically its been testing 10.5, 10.7, 11, and I've been backing OFF my dosing to get this lower, and I just didn't believe it.

I had corals delivered by a local vendor and they nicely tested my alk - 9.0.

I get new reagent, 8.5.

I now have a salifert as a backup when numbers don't seem to make sense, but this testing error that I do not think is my fault is super frustrating.

(Hanna marine master tester, all vials rinsed with rodi and stored with rodi in them).

I think reason could be that after some time the acid in the reagent is contamined (by the pipette for instance) meaning the acid will be less strong. Then the kh results will be false high.

 

[mboley]

Somewhere I read that the Hanna Alk reagent only lasts a month. I found that answer after I started seeing much different readings versus a Salifert test. Frankly I dont remember if it was higher or lower. The owner of Kung Fu corals told me he experienced the same thing and just uses Salifert.

 

[Randy Holmes-Farley Verified Community Expert]

Somewhere I read that the Hanna Alk reagent only lasts a month. I found that answer after I started seeing much different readings versus a Salifert test. Frankly I dont remember if it was higher or lower. The owner of Kung Fu corals told me he experienced the same thing and just uses Salifert.

While I do not use the Hanna for alk, the one month seems excessively short.