another ph variable. Light! I spent all morning in artificial light trying to get my ph right. I was following my process but to no avail!.What was different?I went over everything! I must have have had two dozen ph strips all ;the wrong color. Then the sun came up and I saw that my process was right, the original measurements were right on. Oh, beware the light box, it plays tricks on your color! Another lesson learned, make sure the light source is not drastically different than originally used.