my tap water is 148, leaving 300 RO @ 15, before going into DI vessel.i go through around 1000 litres a week, filling a 220 litre butt up, using pure freedom booster pump, takes around 3 hours to fill 220 litres.i use the 300 RO + 2 10inch DI vessels joined togeather.this is my cheapest option for making pure