OK, no problem. I gave up on PPM right way when I had that 700ppm scale meter. OK, so EC went from .95 to .32 in the reservoir, at 1pm today.@phxazcraig, to make it less confusing you should express EC in millisiemens instead of micro. It's easy to confuse microsiemens for ppm and most people talk in 'milli' when dealing with EC.
It's easy to confuse 320 µS with 320 ppm. 0.3 EC, not so confusing.. haha
I still measure runoff at the end point, when everything has mixed together, plus mixed with what is in the sump bucket. 2pm runoff 1.250, 4pm runoff 1.350.
The more I reflect on this watering system, the more I realize it has been uneven and unknown. Much different than using a watering can. Gotta figure that out for next time.