First let me say that my water is still clear and sparkling because of my test kit....keeping proper chlorine levels in accordance with the chlorine/CYA chart.
I have a Hayward 300# sand filter. I dont have the particulars yet. What is the purpose of backwashing and how do I do this. Also when at the pool store for my first water test (before my test kit) the guy asked about my filter.....it runs at a constant 20psi and drops to zero when I turn it off. What pressure should it be and when and what is involved with a sand change, if that is necessary.
Thanks In Advance