I read a post from 2019 where owner only saw cloudy water in filter window on rinse instead of back wash after replacing sand with filter balls. I have the same experience. Why is this and how do I backwash effectively? I cycled from backwash to rinse several times and lowered pressure 7 or 8 points but a week later pressure is back up 5 points. Is there a special way to backwash with filter balls?