i have 300L tank and run out most days, domestic, top and bottom. but reading posts here I think I am way too generous with the water. Still cant get my head round going over the glass twice and the a quick rinse.......tell me the confidence comes with time!!!!!!!!!! been wfp for 3 months so most houses are on 2nd or 3rd clean. Out of choice I would have 500L available to me so that I could rinse rinse rinse as much as I liked!