Hi
@Noela! 1L is not enough, you must have a runoff in order to flush properly. You don't want to create an over-watering situation either (unless you're having a serious nutrient lockout), so use approximately ~30-35% of your container's capacity, this should give you a slight runoff and won't be wet for too long. If you do it 4 to 6 times on a 10-14 days period, salts/nutrients should be sent out of your medium. To ensure this operation is working, you can use a TDS/ppm-meter and check the runoff values each time you flush, you should see the EC decreasing each time you water. Once this value has dropped close to zero, nutrients have effectively been washed out of the soil! Hope this will help, keep us up-to-date and enjoy your harvest 👊