You are flushing soil that is amended w/ organic nutrients and measuring runoff is not something that’s going to do anything but make you wanna give up growing. For starters those readings are ridiculously high but they are misleading. The organic nutes are present but, since they are organic, are not available to the plant instantly like synthetic bottled nutes.
Now I wish I could tell you how to properly go about balancing soil, that’s amended with an unknown and immeasurable amount of nutrients, with the application of new outside nutrients of your choice. However, this is a riddle that I’ve not been able to solve.
I do know that the folks who have the most success growing in soils like Ocean Forest or Happy Frog tend to keep it simple and allow the soil itself to provide most of what’s needed.
Often the only supplementing being done is a top dressing of more of the same soil around the 5-6 week mark.
Anyway, I hope u get your grow squared away. For the future there is a thread in this site totally devoted to growing in amended Fox Farm soil authored by a fella that lays it out so simple it’s def idiot proof. Check it out.