I use organic nutrients as well, and I do a flushing session every 3 weeks. I use PH adjusted (ph5.8) water with enzymes. After the flushing session I use Mycorhizza spores too get my fungal collony up to strenght again. 2 weeks before harvest I do a thoural flushing session, after that flush I stop giving them nutrients and only give water/mycorhizza/enzymes mix with a ph of 6.0.

But that's only my humble methode.