I've posted a picture of of the colour of a few leaves that are drooping down from my autoflower, do I just pinch these off ( I assumed these are this colour as the buds are drawing more nutes from Lower down ?), she's about 3 weeks from harvest,
No don't take them off ,Auto at the end of flowering use these leaves to draw last nutes and make them taste better. I would flush with your normal routine pH'd .then when pots start to leak, then add 20/30% more again to rinse out any salts or locked nutes . Check the pH of your Ro and and see how they respond.
I am no expert, but that is what I would do.
That leaf you cut has a lot more energy to feed back to the plant. When they’re spent, the color will be almost white, they will come off with just a slight pull, your buds will thank you.