help overfed

Hi I've appeared to overfed her I'm just wondering am I supposed to flush 3 gallon per 1 gallon of soil so if I'm using 50l pot I have to flush 150 litres of water

from what i've read, yes, it's 3x the size of the pot, regardless of unit.
50 L pot * 3 = 150 L of water.

To save myself from using to much water do you reakon I could use GH Florakleen to flush