For the various horticulture applications, I consume between 10 and 20 gallons of RO water each day. (Half of that is used by the Hydrofogger) I also use the RO water for drinking water and making coffee, so add a couple more gallons to that total. So - I chose a fairly costly setup that includes a high capacity filter with a booster pump and a 100 gallon reservoir tank. The whole deal cost about 2K, which I can justify because it produces our drinking water as well - not to mention superior coffee (one of the major food groups!).