i bet the local authority goes APE about your water volume changes!!, dont you get worried about stuff like hose pipe bans , or water restrictions in the summer if ther eis a drought?
i haven't read the entire 31 pages so you or someone else may have mentioned it already, but if your doing 10,000g water changes weekly.............In the last 11 yrs you've changed around 5.7 MILLION gallons of water!!!