Sorry, I mean at the water line.Most bottom paints with copper do turn green at the waterline, I know mine does and nearly every boat in my marina has(I use Micron csc black), you will clearly see a greenish area around the water line. I mean no disrespect,I know you must sell a lot of paint and know more than do I, but I think everyone would agree that if you were to walk threw most any boat yard you will see most boats will be green at the water line.I have never heard of it turning green If that was the case all bottom paints would turn green. We have sold quite a bit of it and the feedback is very good on it. Very bright colors that stay bright and if they get dirty a little scrub will make them look new. They also have a Vivid Free out which is a copper free paint much like Interlux Pacifica.