Hi. So, I seen u growing in soil..
When feeding with nutrients you aren't leaving any excess run off to be soaked up? If so. This might be the cause of it.
Your soil is too hot either way. I wouldn't hard flush. Just leave her eat out what's in the pot for the next wk.
When feeding with soil..
1 feed a wk is enough and you can then give enzyme feeds (no ec, r salts) but just the 1 feed a week..Good luck pal.
The tips turn brown because of nutrient burn. You use too much nutritions. This is just te very beginning from a nutrient burn so good that you noticed it early!
To solve this problem just cut back the nutrients to 75% from your last given dose. The tips that are brown will stay brown and won't recover. But when you cut back to 3/4 of the previous given dose the rest of the plant will stay green and the plant will not be harmed further by overfertilizing.