Damn man, 4 gallons a day is a lot. I do 3 per 4x10 space, so they're about 13.3sq ft each, easily over lb per, and only drink 1 gallon a day. 7 gallon containers of Coco coir + 5% castings, couple mineral powder amendments and dried ground cannabis leaf as an amendment. I do micropulse irrigation, 10 to 16 waterings a day using half gph drippers. I also utilize crop steering techniques, which is basically smart dry backs to manipulate EC throughout the day. It allows me to hit 1.7-1.8ec in the medium for an hour or two daily while only watering 1.3-1.4.
