Hi ppm in run off

Hi guys I have a problem with high ec run off.
I have water of about 0.1 ec and use advanced nutes in coco. I won’t go into too much now and apart from non vigorous vegging I don’t have any issue.
I put 1/2 stated dose of both the cal mag and grow micro bloom.
I had 5 greenhouse cheese, now 3, a king tuts and a critical mass. I made sure I fed none over 1.6 but the run off yrrst on all of them flashed off the scale on my blue lab truncheon. It’s pH perfect nutes and I have tested. I have lowered feed to 0.1+0.9 omitting the cal mag until I see a problem from that. Helps guys this grow was meant to be my first proper one

just to confirm (I use ppm rather an ec) Assume 500 scale
.1ec = 50ppm
1.6ec = 800 ppm normal feed
1.0ec = 500 recent feed
I use a bluelab conductivity pen. Its max reading 5000 ppm
I have had runoff that maxed it out but I was in fox farm OF soil that I loaded up.

Very strange given you are in coco and ec is off the charts.
The first thing that came to mind is do you water / feed enough to consistently get 10 - 15% runoff?
What have your prior readings been? I assume they must have been increasing.
How is your plants doing?