Light green water

[Diane]

I have a 85, 000 gallon pool that started off looking like swamp water. It was the color of black. I have put lots of shock in the pool. The chlorine is above 3 but the pH is very low. I am going to put pH plus in the pool. ( I have put several algecide in the pool and I think that it is killing it because it is very easy to come off the wall. Do I need to start vaccuming the pool. I have backwash the pool several times.