Flush or what to do ?

Ok first things first. Flush your soil with the right pH by following the steps on the Royal Queen Seeds website. https://www.royalqueenseeds.com/blog-how-and-when-to-flush-marijuana-plants-n312 After let the soil dry out completely. From there you need to give nutrients. The EC during this phase should be around EC 1.5 and the pH 6.2 from the solution pH 6.2 (when the plant is using the nutrients the pH runs up a bit thats why pH 6.2). You need to use the righ nutritions. Your plant is in pre flower. You need a basic blooming nutrition. This contains less nitrogen (N), and more phosphorus (P) and potassium (K). Your plant needs the phosphorus (P) and potassium (K) during blooming to make the buds. When the buds start to swell (around 2 weeks from now). You can cut the basic blooming nutrient a bit till EC 1.2 and add a PK-Booster like PK 13/14 till your solution reached EC 1.6 This should do the trick till the last week then you just need to flush the soil for harvest (use the same article from RQS that I send you earlier). Enjoy your grow!