I have used synthetics with and with out ACT teas and have had amazing white root balls. One outdoor grow, my first, was with miracle grow nutes and no bennies with straight tap water and the roots were really white and healthy. I can all so tell the difference in growth and health when using Beneficials with synthetics. You said soil PPM / do you mean nutrient PPM ? That's interesting that they will continue to thrive under 900 and hate P. Now I understand why my mentor stops adding Bennies in flower because of boosting P organically. What happens when they take over ? I think I've seen that before and wondered what's up ? Like everything I do, I tend to over do it. lol . This year Im shooting for straight organic unless I have a problem I need to fix fast, which I doubt. One thing I can say is I have been top dressing and feed quano teas twice, They are looking fine but just seem a little off on color and vigor. Yesterday they all got Bennie and kelp tea and tonight I can all ready see the change in them. The dark green and velvet feel to the leafs.