I'm having problems reading the results for this test. I have read the directions several times and watched the YouTube video! I completely understand how to use the kit. The problem is I don't get the end color blue. The test goes from red to purple then violet. I've even tried it drop by drop after adding the first 0.4 ml and around 0.6 i get the purple like its about to turn blue then any additional drops violet. Has any one else had this issue?