Run-off water pH too high

[Mjmjm]

I am measuring the pH with a pen. Watering every 2-3 days, giving 1L of pH-ed water with calMag. I have 60g of "easy boost" mixed in my coco (check picture).
Plant is in vegetative stage, slowly dying (check my other post).

[Toker1]

Your root zone ph is way too high. Lower it by flushing with 5.5 water. Stop flushing when the run off is closer in ph to the water going in.
Here is the quick and dirty explanation... let’s say you water with 5ph and it comes out at 6... you can assume your root zone ph is about 7. Hope that makes sense.

[Mrblu]

What are you using to measure the ph - pen or drops? What nutrients do you us use? Is your runn off container clean. Walk us through your method a little bit more.

[Mjmjm]

Although the pH of the water I'm using to water my plant is in the range of 5.5 - 6, the drainage water is coming off with a pH range of 7.5 - 8.3. I'm using coco mixed with perlite. Why is this happening? And how can i fix it?