I read somewhere that suggested about 80% of the usual recommended amount. Another source said to use about half. I noticed that if I backwash several (shorter) times in succession - on/off with the pump for maybe 10 seconds each - then returning to regular operating flow in between to see what the gauge reads - the pressure is less after doing the successive shorter backwashes rather than if I do one long one (typically for about a minute). I usually always take the tank apart every time, but with the insanely short filter cycles I'm having, I want to experiment at least for a brief period with not always taking apart the tank - gets old after doing it every 3-4 days (actually now down to a single 24-hour period).