Hello from Edgecomb, Maine. I filled my pool from our well, bought a sand filter pump. When I mistakenly added powdered shock to the water it instantly turned green. I have been filtering and back washing for a couple days, and the water is just about clear again. but now my f2 level is back to 0. I am not sure what to add for chemicals so I don't get the green back. This is an Intex 18 X 52 above ground pool. Just used poolmaster test strips and my alk and ph are spot on