Getting lower EC runoff Coco

[herojuana.tom]

I would say no need to empty per-se… You can make a small amount of a higher EC feed solution and use it to top off your reservoir to raise the reservoirs EC without wasting your already nearly perfect nute mix. As things seem to be perfect already, minus the slightest yellowing you observed, you could just add a little cal mag to your reservoir as Cal Mag is the last ingredient to be added anyways so it would not hurt to add it now.