My pool is a walmart type above ground pop up pool with a PVC frame, with a sand filter. (I just learned about the BBB method & now understand why I am having problems but need help correcting it. I'm hoping I'm on the right track). The water turned green, and the lady at the pool store advised me to double the amount of shock & swim, & when that didn't work to use a very small amount of algecide. It sort of worked but now the water is a cloudy blue. The pH was so low it was off the chart but after reading about BBB I have effectively raised the pH using 20 mule a borax, but I'm not sure of what step to take next to get my water clear again? . I really need to correct without draining & starting over if possible. Please help