Accidentally poured in more water above the net pot, corrected ph6.3 to ph5.7 then added great white. Out of sudden, leaves started to droop badly.

take some of that water out, you want that space between your roots for oxygen your plants roots are not getting the air they need. also your ph is way too high for what your doing your ph dropped over night, change out your nutrients every other day. you want to try to keep them at the sweet spot between 5.8-6.0 but first things first run plan 6.0 ph ed water for 24 hours, add your nutrients use a very small amount of the great white every 3rd feed. hope this helps

Eseoteric_grower is on track, the PH rising is likely due to an infection. One suspect is Cyanobacteria (blue algae), are the roots slimy to the touch? Also called root slime... Basically suffocates hydro plants they look like this. Eventually the res turns to a slimy mess... We need more info... have you been using H2o2? Did res temps rise, air pump die? Are your air stones suitable for the volume of water in your buckets? - Cyanobacteria is actually a aerobic bacteria so airstone actually feed the bacteria. Great white is a mycorrhizae product that’s overly expensive for what you get... Once a mycorrhizae colony has built up on the roots you don’t need to add it again... Hydroguard is better option for a healthy res tank. And cost effective... You can chat in the comments just link @PharmaZ

I have seen this happen before when the air pump fails or stones are blocked or the water temp is too high. I wouldn’t have thought the water above the bottom of the net pot would do that on its own.