Hello,

 I'm trying to use post-import custom calculation 10 to convert nitrate as N to nitrate as NO3-. I am receiving the error "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index or redefine the index to permit duplicate entries and try again.'

Some of my results do have both nitrate as N and nitrate as NO3 from the raw lab data but most of them only have nitrate as N. I don't need ESdat to calculate and overwrite the locations where the nitrate as NO3 data already exists. I looked at the raw query and it looks like it is only supposed to operate on samplecodes where the parameter to be calculated is null so I'm wondering if something else is causing this message? What else should I look for?

 Thank you,

Theresa