Don't focus on the bottom leaves. You had a problem, you over fed, you flushed. Correct procedure. But how does the new growth look? Is it healthy, is it fast? Pick of the lower damaged leaves and discard them. Lay off the nutes especially as you're using a well fed soil with microbes in, what you really want for that soil is organic nutes and molasses - these will help feed your microbes, advanced nutrient line wont do that and will just overload your soil with nutes the plants can't handle. Good luck moving on, message me if you want ๐ฑ๐