testing for copper

[dwint]

i have cuprisorb in my fishless tank for a day and ahalf now and still no change in color.when testing for copper its reading 0.2.i have it in a sock above a high flow bubbler and still no color change.is it just too soon?

 

[dwint]

i read the directions better and it said to take the cap off and look 8 inches away and now it is green which is 0 so i am copper free.i was wondering why the cuprisorb wasnt turning blue