Hello; One other thing came to mind. The test vials are small so any contamination can skew results. Get some distilled water (DW) or DI water and use it to clean the vials. You can also let the vials sit full of DW for a while. Picked this up from
duanes
.
You can also use DW as a standard. Run the tests on the DW and the results should be neutral or zero for most anything.
You can also use DW as a standard. Run the tests on the DW and the results should be neutral or zero for most anything.