See that's what I thought. Someone told me on here when I did a slurry test that came out to 140 ppm that there was a 10x feature on my tester. So 140 meant 1400. So I flushed and did pure water and it got worse
forget slurry tests, runoff ppm and all that garbage. pay attention to the plant overall, new growth, and what you put into it. your ph target is correct, she just wants food, specifically P.
feed, feed, water. pour solution over entire medium and let it flow through it. should have plenty of runoff, some say 10%-20%, whatever. the point is have runoff so you dont get nutrient buildup.
lastly, place the plant, if possible, in a spot that has less intense light. it will allow it to recover without creating as much further damage.