how do i flush hydroton with plants growing in it?

I didn't flush my hydroton properly before reusing it and the plants are starting to show signs of nutrient overdose, i have tested ph, ppm and temperature, my conclusion is that the salt/nutrient buildup is overfeeding my plants in combination with the nutrient solution i'm giving it now. How can i flush without taking the plants out?

I am not hydro, but I think your question was the answer.

Question should be:
1.) How to I remove excess nutrients from previously used hydroton.
a> Flush it with water.

More specifically, just run a bunch of water through it, then dump out your res.

GH Flora Shield is something you could consider. Safe for growing plants and will help to remove toxins from the roots and medium. Check it out on the GH site. Peace