approx. water per plant

about how much water would six plants use per feeding? not looking for exact amounts, just something to use to get an idea of how much nutes to buy. veg under 400 mh, flower under 1k hps

per feeding?well u have to mix the nute in for 6x the feeding since your watering 6 plants.,.,.,.,so it would basicaly be a mix ratio set for safe use without nute burning the plants,also start a litle lower when mixing in bulk to make sure the mix is not to strong