Safe ppm runoff numbers for final flush harvest?

[HigherTheHigh]

hi everyone

iv never used a ppm meter up until now

seen alot of mixed results, some say 100ppm is minimum and some are saying 600ppm

whats a safe ppm reading to no when i can chop?

if the meter reading shows up a safe reading after mid runoff does then that mean all the nutes will be out the plants or not?

growing in coco/perlite

using tap water to flush, ph is usually around 6.2 6.4 (plants have had tap water all through there life)

thanks guys, always appreciated

 

[HigherTheHigh]

my tap water ppm is 107ppm

anyone?

 

[Kip22]

General rule of thumb is about two weeks of just water for a pre cut flush. Assuming you are getting about 10-20% run off each watering and watering only when they are just about dry u should be fine.

 

[HigherTheHigh]

i already no all that but im after the numbers to no for sure
iv flushed 20L pots with nearly 120L then water when there dry and still have a slight chemical taste
thanks for the reply