When in doubt, drain it out.
I'd consider draining the system out, continue introducing pure water so as to dilute and evacuate the system anywhere between 200-300% the total volume of the system.
Have water filled to 1/2 way up the net pot so as to submerse and leach the salts & root debris clinging to the roots.....pulling them into solution to be drained away. Run something like
clearex for a day or so.
This would also be a time to run a mild Hydrofungicide/ Zone treatment with the
clearex solution to reguvinate the roots and reboot the the microbial villages.
Then drain this leached solution away and introduce a fresh batch of nutrient solution that you've pre-balanced in a side resy. Start the new batch in a side resi the day you drain the system so as to allow for 24+ hrs for the solution to stabilize if any pH adjustments are made.
Introduce some bacillus in the solution and a fungi blend in the root crown after you've ran you're root cleansing .
Sorry bout the wordiness.