It depends, if you have ongoing controls in your water system: UV light, a filter, continuously ozonated tank but not necessarily the loop you can get away with longer time between sanitizations. If you have no ongoing controls in your system and you don’t have the barrier from controlling the amount of bugs that gets through your recently purified water into tanks, you might have to sanitize it weekly. So there is no standard time because there is no standard water system. So it depends – I have seen some doing it quarterly but frankly quarterly is a stretch even for good water system especially for those that have good ongoing controls so I really cannot give you the standard amount because there is no standard frequency for that monthly or quarterly I see being done a lot.
