Hey Pal. You are in lockout.
You don't need to hard flush. That's just added stress. At this point. And will confuse your process.
For the next week. All you gotta do. Is cut all ferts and just 1L or whatever she takes a day and she'll slowly start to eat what's there. If you wanna do a flush. Which you don't need to do. Put towels or something that soaks up water pretty fast around your pots and try get them placed under the pots a few layers and take out, squeeze, and repeat. I've a few more ideas. But this will be your best bet if you wanna flush early to srtv this out quick. But soft flushing until you see your plant in need of some feed, (yellowing, or very light blotchs on her as she's in flower so it'll more likely be signs of wanting PK. anything with N pull back for the next 2 weeks. As your leafs are holding enough N to pull you through. The bottom ones will turn yellow 1st and when she's drained.. then start adding a more substantial N nutrient.
Feel free to DM me in anything with flushing, as my next project is a scrog and I've been looking up how to fix issues like what it you need to flush or turn your plant that's been shaded out. (Simple really, just move your light. And a few other things)
Hope you solve it. Good luck.