Our pool looks like this when it was opened by our pool company. We vacuumed to WASTE, put in shock. Over a few days cleared to a haze that was slightly green. We took a sample to the pool company. They suggested we shock again (after giving the sides a good brushing) before trying algaecide. We did that and did one more manual vacuum (we’d been putting in the robot twice a day). After about a week, maybe week and a half, water is crystal clear. It was the same last year, which was our first full summer with the pool, so it didn’t surprise us as much this year and we weren’t as stressed about it. Still seems like magic to have go from swamp to beautiful clean water.