Technical question: What's everyone's take on runoff pH? Should I even worry about it if input ppm/pH is in range? I know ppm can be watched easily and if it starts climbing to back down the feed strength or up the input volume and runoff amount. If the runoff pH is dropping precipitously should I change anything or not worry about it?
I've been running in at about 520ppm for the last couple weeks and varying pH going in from 5.8-6.2 sticking to 5.9/6.0 as much as possible. Runoff ppm is sticking in the mid 400's, crept up to 615 but some extra volume brought it back to near 550 again. Typical irrigation volumes have been 250-300ml and getting an average of 70ml runoff, 20-30%.
However, runoff pH has dropped from 5.5 to 4.3 or lower! I watered in 520ml split between 7am and 3pm sessions. It went in at 520ppm and 6.1pH. Measured runoff before the evening watering at 198ml of runoff reading 424ppm and 4.0pH. I expected higher than usual runoff volume as I am less busy and can water 3x a day.
I was worried the runoff pH is far too low and there could be a salt build up despite the ppm numbers not suggesting it. I did calibrate the pH meter in case that was the culprit.
I just ran a full 1000ml of 400ppm 6.3pH through the cup. I broke it up into 4 250ml waterings.
4x250ml in with runoff at:
1) 112ml out 339ppm 4.6pH (evening watering)
2) 240ml out 365ppm 4.4pH
3)250ml out 385ppm 5.3pH
4)250ml out 392ppm 5.2pH
Should I worry about runoff pH at all or am I chasing a non problem? Plant looks fine except for maybe 4 leaves here and there.
