I'm merely a parrot here........my hydro guy says you can check runoff and determine IF you need to flush by the numbers (he says he usually will flush with a number around 900ppm) and then AFTER flushing he likes the ppms around 300 so Reaper you don't try to be as exact with it as with hydro. My understanding of this is that its much more for overnuting than ph in this case........but he SWEARS by it.

I agree Stink.....most soil growers DONT have e.c. meters to measure that stuff with. And while YOUR eagle eye (and eagle tongue ) may be able to see when something needs flushing etc....NEWB soil growers like me need all the help we can get.
Weedhound Reviewed by Weedhound on . Soil Runoff pH, Flushing to correct lockouts- Why and how to do it! This is a common question that comes up when troubleshooting, so I thought I'd post up a little summin summin. Why do you want to know your runoff pH? Simple- it's an indication of how your water, fertilizer, and grow medium are interacting chemically. There are 3 measurements that are important to know when you are caring for plants growing in a soil or soilless medium. The first is the pH of your source water. Next is the pH of your nutrient solution after the fertilizers and Rating: 5