How much water for marijuana

A question from a fellow grower:

We have a few plants and have wondered how much water they should have.

Plants are in coco peat and growing in 30 liter pots under two 600 watt lights. The watering is done by hand.
After years of up and down success we’re really making the BIG effort to get things right (Dedicated grow tent Etc) correct ph and
the correct amount of nutrient etc etc.

Well; Watering should drench the pot. Assuming you have plant saucers. Water until the saucer fills up. Then do not water again until medium is almost dry.