i know this was posted a while ago but i just came accross it
i think you may be using opk's i have never seen a green hcg test, i always thought opks are always green and hcg's are always blue so people dont get mixed up, you should really find out if the test IS actually an hcg as i wouldnt want you getting your hopes up in the future thinking its a bfp if its opk's your using.