I actually compared slurry and run off i took a slurry then watered till run off tested both.
Slurry i was at 6.5pH and 200 ppm?
Run off was 6.2 pH and 1600 ppm?
Maybe the pH was the same but the PPM were drastically different it’s in my grow diary id have to go back and look at it but it sold me on slurry over run off.
I also think bottom line as long as you’re consistent on using the same test you won’t have a problem. Just know that when you’re doing run off you’re pushing out whatever the plant didn’t use. This Is how Scott explained it to me and someone else in my diary. And i know Scott also said that the first 2 3 inches of soil are feeder roots where majority of your nutes will be taken in from the plant.
This is also why i decided to opt out of heavy flushes and just fed herc SLF and AE till the last week then it was herc to bring down my pH of the water if i got run off cool if i didn’t NBD. But because if excess is getting pushed down and not really being taken in what’s the point of flushing it all out. It was an experiment for me haha