Alk test results

[Mschmidt]

All,

I recently got a Hanna Alk tester as I trust it to remove more user error in testing. here is my issue: using my old drop checker (seachem I think, I can check when I get home) I would consistently get readings near 4-5 dkh. when I tested with the Hanna checker, new test but expired (4/22) reagent (didn't look at it in the store)i get a reading of 10+ in one tank and close to 13 in the other.

Method for testing with the color change: with a clean pipet fill cup with tank water, put 1 drop reagent in, stir, repeat till color change (usually 8-9 drops), divide by two per directions for Dkh.
Method with Hanna: fill clean cuvette with tank water, invert a few times, get baseline reading, add reagent and mix, clean outside of cuvette with old t-shirt rag, get results. multiply ppm by .056 for dkh.

 

[Timfish]

When I got my Hanna alk I checked it with a freinds. Using both reagents in both testers witht he same sample of water we got a difference of .9 dKH between high and low. Does that big a difference matter, probably not, researchers are using the meq method which is a lot less accurate than the dKH method. But I went back to API as it's easier and was clearly as accurate or more accurate than Hanna's alk.

 

[Randy Holmes-Farley]

Does that big a difference matter, probably not, researchers are using the meq method which is a lot less accurate than the dKH method.

What does that mean? The unit of measure used is not an indication of the method used to generate a value.