I posted above, mine makes 50 gallons of water a day. My tank is 3.4 gallons and that taked about 1.5-2hrs to refill, so reservoir isnt necessary for me. You can ha e it drain into 1 if you wanted. That should meet your water need. Super good deal on Ebay with extra filters included. You can get ones that make more or less. I cant imagine growing without it. If you need 4 gallons a day a 3 gallon tank is big enough, just look at how many gallon it can do. I get some in the morning about 3 gallons and I let refill a couple hrs I get more if needed. I get a head and I fill up gallon jugs. It's under kitchen sink sits in back corner. You maybe able get bigger tank maybe a 5 gallon have to look. Good luck stay lifted.
