i have a 10x10 tent, and i use a 50 gallon drum that is placed on top of a stand. making the bottom of it about 3 feet high from the floor. this gives me enough pressure to water without any pump. i siphon the water the first time and have a valve to turn it on and off and to keep it primed. i bring the treated water in from the floor thru a porthole of the tent that was made for such stff in the corner of it. i keep all my electric overhead and all my water at the ground and waist level. except for the misting system… it raises up from the floor to the ceiling from the water line direct, it goes into a manifold and splits into the 3/8" adapters for the misting line. i use the line direct from the pipes for the pressure needed to fog the room, giving it the rise in humidity that is needed and to cool it at the same time. because it hasn’t been treated i have to occasionally soak the emitters in phosphoric acid to clear any plugged emitters from the build up of calcium of the hard water that i have. the phosphoric acid is what i use to adjust the ph of my water supply, because of its hardness. i also have 2 reverse osmosis filtration units inline to my water reservoir, they are the hydro-logic brand 200gallons per day and are the 3 stage variety., they treat the water before it enters the reservoir barrel. it then drains into a 35 gallon barrel that i use as my mix tank. it is on the floor and the mixed water i have to hand dip into a 2 gallon bucket when i feed. i feed every other time that i water and i water twice a week. i am wanting to set up a drip system but have not as yet. hop this helps out on your project, and good luck, a 20 foot is basiclly twice of what i have, and sounds like a lot of work.