What to do next?

[tmmort]

Why not just drain and refill?

[JohnT]

Why not just drain and refill?

Hard to reset a used liner, and water cost can be $500 in some areas.

[bcb1]

You can't drain a vinyl liner pool - at least not safely. The water provides an enormous amount of weight. Take it out, the liner will move/stretch, and likely tear, probably in multiple places. Never, ever drain a vinyl liner pool more than 1/3.

I've heard pool guys say that it's possible if you use sandbags to weigh down the liner at the edges and deep end, but even then it's dicey.

Even if your water is brown/black/deep green, it'll clear up. Keep vacuuming to waste, keep your FC level up to 12-15ppm, and run your filter 24/7. It might take several days, it might take a week - but it will clear.