I known this is really old but I am having the same problem. My pool is only 2 days old. I did the whole sand filter start up and it blew what looked like dirty water back in my pool and turned the entire 16x31 foot pool green in minutes. Tried it again after placing a shock and backwashing the next day and it did it again. Did you ever figure it out?
Moved from here.
Moved from here.
Looks like your post was moved to its own thread, so let's start fresh with your situation. Please post a full set of water test results from your TF-100 or Taylor K-2006C test kit. That's generally step #1, espcaially when it comes to dscolored water. Also update yoru signature with all of your pool and equipment info. If you are on a well include that too.